Radiopharmaceutical and methods

ABSTRACT

The radiopharmaceutical 177Lu-PSMA I&amp;T is provided, including in high purities with extended shelf life. Further provided are methods of synthesis of 177Lu-PSMA I&amp;T and pharmaceutical compositions and methods of treatment that comprise 177Lu-PSMA I&amp;T.

This application in a continuation of U.S. application Ser. No.17/374,984 filed Jul. 13, 2021, which claims the benefit of U.S.provisional application number 63/051,335 filed Jul. 13, 2020, and U.S.provisional application number 63/143,664 filed Jan. 29, 2021, all ofwhich applications are incorporated by reference herein in theirentirety.

FIELD

The radiopharmaceutical lutetium ¹⁷⁷Lu-PSMA I&T including opticallyenriched mixtures thereof are provided, including in high purities withextended shelf life. Further provided are methods of synthesis of¹⁷⁷Lu-PSMA I&T including optically enriched mixtures thereof andpharmaceutical compositions that comprise ¹⁷⁷Lu-PSMA I&T includingoptically enriched mixtures thereof.

BACKGROUND

Radiopharmaceuticals have been used for a variety of therapeutic anddiagnostic indications. Among others, radiolabeled molecules have beenuseful to treat various malignant tumors.

Use of these pharmaceutical agents presents certain challenges,including with respect to the formation of the active pharmaceuticalingredient by combination of a radionuclide with a targeting agentwhereby the resulting active pharmaceutical ingredient has low purity.Furthermore, the subsequent formulation of the active pharmaceuticalingredient to form a pharmaceutical agent has poor stability anddecreased shelf-life. In particular, therapeutic compositions comprisinga radionuclide may undergo radiolysis during any one or more offormation of the active pharmaceutical ingredient, preparation of thepharmaceutical agent and storage of a pharmaceutical composition. Duringradiolysis, radionuclide emissions may react with other groups of theactive pharmaceutical ingredient thereby resulting in decomposition ofthe active pharmaceutical ingredient and a reduction in purity whichlimits the shelf-life and clinical usefulness of the pharmaceuticalcomposition.

It thus would be desirable to have new pharmaceutical agents. It wouldbe particularly desirable to have such agents that exhibit improvedpurities, stability and shelf-lives.

SUMMARY

We now provide, inter alia, ¹⁷⁷Lu-PSMA I&T having high purity, methodsof preparing the compound, and pharmaceutical compositions and methodsof treatment comprising ¹⁷⁷Lu-PSMA I&T.

More particularly, we now provide ¹⁷⁷Lu-PSMA I&T in high puritiesincluding for extended storage times. We also provide ¹⁷⁷Lu-PSMA I&T inthe absence of undesired impurities.

We also have found methods for producing ¹⁷⁷Lu-PSMA I&T undercomparatively reduced reaction times and/or temperatures. We also havefound that such methods can produce ¹⁷⁷Lu-PSMA I&T in enhanced purities.

Still further, we have found additional methods for producing highpurity ¹⁷⁷Lu-PSMA I&T, including by at least substantially or completelyexcluding gentisate compounds from the reaction to form ¹⁷⁷Lu-PSMA I&T.

Still further, we have found that gentisate compounds can form adductswith ¹⁷⁷Lu-PSMA I&T during the formation of ¹⁷⁷Lu-PSMA I&T.

We have also surprisingly found that addition of one or more ascorbatecompounds to the formed ¹⁷⁷Lu-PSMA I&T can significantly enhance shelflife of the ¹⁷⁷Lu-PSMA I&T, including maintaining high radiochemicalpurity over extended storage times. We have also surprisingly found thataddition of one or more gentisate compounds to the formed ¹⁷⁷Lu-PSMA I&Tcan significantly enhance shelf life of the ¹⁷⁷Lu-PSMA I&T, includingmaintaining high radiochemical purity over extended storage timeswithout forming impurities, including gentisate adduct impurities.

In certain aspects, optically enriched mixtures of ¹⁷⁷Lu-PSMA I&T areprovided.

¹⁷⁷Lu-PSMA I&T is a complex of lutetium (¹⁷⁷Lu) andEuK-Sub-kf-iodo-y-DOTAGA. The term “complex” herein generally refers toa union of ¹⁷⁷Lu and the ligand EuK-Sub-kf-iodo-y-DOTAGA inclusive ofchemical and physical variations that may exist with the joined orassociated lutetium-177 and EuK-Sub-kf-iodo-y-DOTAGA (designated as¹⁷⁷Lu-PSMA I&T).

EuK-Sub-kf-iodo-y-DOTAGA and ¹⁷⁷Lu-PSMA I&T each has several possiblestereoisomers, including the R and S isomers of the carbon that is anN-ring substituent of the tetraazacyclotetradecane moiety of thosecompounds. References herein to EuK-Sub-kf-iodo-y-DOTAGA and ¹⁷Lu-PSMAI&T without further limitation includes all possible stereoisomers ofeach of those compounds and particularly both the noted R and S isomers.

In certain aspects, racemic mixtures of ¹⁷⁷Lu-PSMA I&T andEuK-Sub-kf-iodo-y-DOTAGA are provided, including for use in the presentpharmaceutical compositions and methods.

In other preferred aspects, optically enriched mixtures of ¹⁷⁷Lu-PSMAI&T and EuK-Sub-kf-iodo-y-DOTAGA are provided, including for use in thepresent pharmaceutical compositions and methods.

In a preferred aspect, R isomer-enriched EuK-Sub-kf-iodo-y-DOTAGA isprovided, i.e. EuK-Sub-kf-iodo-y-DOTAGA that is comprised of a weightexcess of the R isomer (referring to the *carbon having N-ringsubstitution) of the following structure 1A:

In this aspect, generally preferred is EuK-Sub-kf-iodo-y-DOTAGA that issubstantially optically enriched with the R isomer of structure 1A, oris an enantiomerically pure mixture of the R isomer of structure 1A.

In another aspect, S isomer-enriched EuK-Sub-kf-iodo-y-DOTAGA isprovided, i.e. EuK-Sub-kf-iodo-y-DOTAGA that is comprised of a weightexcess of the S isomer (referring to the *carbon having N-ringsubstitution) of the following structure 1B:

In such aspect, generally preferred is EuK-Sub-kf-iodo-y-DOTAGA that issubstantially optically enriched with the S isomer of structure 1B, oris an enantiomerically pure mixture of the S isomer of structure 1B.

Additionally, in certain preferred aspects, the R of ¹⁷⁷Lu-PSMA I&T isprovided, including for use in the present pharmaceutical compositionsand methods. That R isomer may be represented by the following structure2A:

In this aspect, generally preferred is ¹⁷⁷Lu-PSMA I&T that issubstantially optically enriched with the R isomer of structure 2A, oris an enantiomerically pure mixture of the R isomer of structure 2A.

In another aspect, the S isomer of ¹⁷⁷Lu-PSMA I&T is provided, includingfor use in the present pharmaceutical compositions and methods. That Sisomer may be represented by the following structure 2B:

In this aspect, generally preferred is ¹⁷⁷Lu-PSMA I&T that issubstantially optically enriched with the S isomer of structure 2B, oris an enantiomerically pure mixture of the S isomer of structure 2B.

The present ¹⁷⁷Lu-PSMA I&T compound can exhibit particularly favorablechemical or radiochemical purities, including greater than 95, 96, 97,98, 99, 99.5, 99.6, 99.7, 99.8 or 99.9 percent radiochemical purityand/or substantial absence of one or more prior impurities.

Thus, significantly, ¹⁷⁷Lu-PSMA I&T is now provided for the first timeat the high purities as disclosed herein, including with the absence ofprior impurities.

Additionally, new methods have been found to produce ¹⁷⁷Lu-PSMA I&T withhigh (e.g., >99 or 99.5 molar percent) incorporation of lutetium-177.Surprisingly, the present methods can provide such high lutetium-177incorporation under mild conditions, including reduced reaction timesand/or reduced reaction temperatures.

More particularly, in one aspect, methods are provided for preparing¹⁷⁷Lu-PSMA I&T that include admixing lutetium-177 andEuK-Sub-kf-iodo-y-DOTAGA in the complete or substantial absence of oneor more gentisate compounds.

It has been found that at least substantial absence of any gentisatecompounds during the incorporation reaction (including heating) cansubstantially reduce impurities that would otherwise be produced throughlutetium-177 incorporation. That is, it has been found that exclusion ofany gentisate compounds from the reaction to incorporate lutetium-177with EuK-Sub-kf-iodo-y-DOTAGA can produce lutetium ¹⁷⁷Lu-PSMA I&T withreduced impurities. See, for instance, Examples 1 and 2 which follow.

Gentisate compounds would be substantially absent (or an admixturecomprising lutetium-177 and EuK-Sub-kf-iodo-y-DOTAGA would besubstantially free of gentisate compound(s)) if one or more gentisatecompounds are present in an amount of less than 10, 8, 5, 4, 3, 2, 1 or0.5 weight percent relative to the weight amount of one or more otherstabilizer compounds (including ascorbate compounds) present during anincorporation reaction.

As referred to herein, “the incorporation reaction” or similar termrefers to the reaction to incorporate (e.g. complex) lutetium-177 withEuK-Sub-kf-iodo-y-DOTAGA to thereby produce ¹⁷⁷Lu-PSMA I&T. In certainaspects, the incorporation reaction may include admixing lutetium-177with EuK-Sub-kf-iodo-y-DOTAGA and heating thelutetium-177/EuK-Sub-kf-iodo-y-DOTAGA admixture.

Methods also are provided for preparing ¹⁷⁷Lu-PSMA I&T that includeadmixing lutetium-177 and EuK-Sub-kf-iodo-y-DOTAGA in the presence ofone or more ascorbate compounds suitably in an aqueous composition. Theone or more ascorbate compounds may be referred to as a component of the“Reaction Composition” or similar term when added to or otherwisepresent with either lutetium-177 or EuK-Sub-kf-iodo-y-DOTAGA as part ofthe reaction to incorporate (e.g. complex) lutetium-177 withEuK-Sub-kf-iodo-y-DOTAGA to prepare lutetium ¹⁷⁷Lu-PSMA I&T. TheReaction Composition is suitably an aqueous composition.

The Reaction Composition may comprise one or more other agents,particularly one or more distinct organic compounds in addition toascorbate compound(s). Such additional distinct organic compoundssometimes are referred to herein as “stabilizer compounds.” The term“stabilizer compound” or “stabilizer compounds” includes one or moreascorbate compounds.

In particular aspects, the EuK-Sub-kf-iodo-y-DOTAGA precursor (structure1A and/or 1B) may be diluted before admixture with a lutetium-177compound, such as diluting a compound of structure 1A and/or 1B with anaqueous composition preferably comprising one or more ascorbatecompounds.

It has been found that the presence of one or more ascorbate compoundsduring the incorporation reaction (including heating) can substantiallyreduce impurities that would otherwise be produced through lutetium-177incorporation.

In particular, it has been found that the presence of one or moreascorbate compounds during the incorporation reaction (includingheating) can substantially reduce impurities that would otherwise beproduced through lutetium-177 incorporation in the absence of aradioprotectant or in the presence of gentisic acid, for example where agentisate adduct is formed with ¹⁷⁷Lu-PSMA I&T.

In preferred systems, one or more ascorbate compounds are present duringthe incorporation reaction (including heating) together with at leastsubstantial absence or preferably complete absence of one or moregentisate compounds during that incorporation reaction to reduceimpurities that would otherwise be produced through lutetium-177incorporation. In such an aspect, gentisate compound(s) would besubstantially absent (or an admixture comprising lutetium-177,EuK-Sub-kf-iodo-y-DOTAGA and one or more ascorbate compounds would besubstantially free of gentisate compound(s)) if one or more gentisatecompounds were present in an amount of less than 10, 8, 5, 4, 3, 2, 1 or0.5 weight percent relative to the weight amount of one or moreascorbate compounds present during an incorporation reaction.

It has been found that a substantial or complete absence of one or moregentisate compounds during the incorporation reaction can reduce oravoid the occurrence or formation of an impurity that has been detectedby high-performance liquid chromatography (HPLC).

The impurity or impurities that has been observed upon use of one ormore gentisate compounds such as gentisic acid during the incorporationreaction to form ¹⁷⁷Lu-PSMA I&T is sometimes referred to herein as“gentisate adduct impurity”.

In one aspect, a “gentisate adduct impurity” as referred to herein hasbeen characterized as have a retention time in the region of 10.2minutes by high-performance liquid chromatography (HPLC) with a byhigh-performance liquid chromatography (HPLC) with a Waters)(Bridge BEHPhenyl-Hexyl Column, 130 Å, 3.5 μm, 4.6 mm×150 mm using 0.1%trifluoracetic acid in water (Mobile Phase A) and 0.1% trifluoraceticacid in acetonitrile. A linear gradient from 85% Mobile Phase A to 55%Mobile Phase A over 12 minutes is used and the ratio is held for 15minutes. The absence of such impurity would be demonstrated by a nopeaks (e.g. by visible review of spectra) being present in the 9 to 12minute region of an HPLC chromatogram corresponding, in particularaspects the 9 or 9.5 to 10.5 or 11 minute region or the about 10.2minute region as exemplified by the radio chromatograms of FIGS. 1C and1D.

In another aspect, a “gentisate adduct impurity” as referred to hereinmay be characterized as a compound that include a covalent linkage of 1)a gentisate compound such as gentisic acid or reaction product or otherderivative of such gentisate compound and 2) EuK-Sub-kf-iodo-y-DOTAGA.

For instance, without being bound by any theory, gentistic acidoxidation can result in formation of a benzoquinone as shown in thefollowing Scheme 1.

That benzoquinone then may covalently couple withEuK-Sub-kf-iodo-y-DOTAGA during the incorporation reaction, for exampleto produce Adduct Compound Structures A1 and/or A2 (mass 1803 g/mol) asgentisate adduct impurities.

In a further aspect, suitably a composition (sometimes referred hereinas the Formulation Composition and distinct from the ReactionComposition) is added following or upon termination of heating of thelutetium-177 and EuK-Sub-kf-iodo-y-DOTAGA particularly where a complexof lutetium-177 and EuK-Sub-kf-iodo-y-DOTAGA has been formed.

In particular, we have found enhanced stability and shelf-life of theformed ¹⁷⁷Lu-PSMA I&T can be achieved by treatment of the incorporationreaction composition with one or more gentisate compounds following orupon termination of the reaction heating step.

Thus, methods are providing for preparing ¹⁷⁷Lu-PSMA I&T, comprising a)admixing 1) lutetium-177 and 2) EuK-Sub-kf-iodo-y-DOTAGA; b) heating theadmixed 1) lutetium-177 and 2) EuK-Sub-kf-iodo-y-DOTAGA, wherein acomplex of lutetium-177 and EuK-Sub-kf-iodo-y-DOTAGA is formed; and c)adding one or more ascorbate compounds while or after the heating isreduced or terminated. In certain aspects, both 1) one or more gentisatecompounds and 2) one or more ascorbate compounds are added while orafter the heating is reduced or terminated.

In a particular preferred embodiment, a gentisate compound is added tothe formed complex of lutetium-177 and EuK-Sub-kf-iodo-y-DOTAGA promptlyafter the termination of the heating step, for example within 0.25, 0.5,1 or 2 minutes of initiation of termination (complete removal of heatingsource, or the occurrence of an at least 20° C. temperature drop) of thelutetium-177 and EuK-Sub-kf-iodo-y-DOTAGA incorporation reaction.

In yet a further preferred embodiment, both 1) a gentisate compound and2) an ascorbate compound are added to the formed complex of lutetium-177and EuK-Sub-kf-iodo-y-DOTAGA promptly after the termination of theheating step, for example within 0.25, 0.5, 1 or 2 minutes of initiationof termination (complete removal of heating source, or the occurrence ofan at least 20° C. temperature drop) of the lutetium-177 andEuK-Sub-kf-iodo-y-DOTAGA incorporation reaction.

In an additional embodiment, preferably an ascorbate compound is addedto the formed complex of lutetium-177 and EuK-Sub-kf-iodo-y-DOTAGApromptly after the termination of the heating step, for example within0.25, 0.5, 1 or 2 minutes of initiation of termination (complete removalof heating source, or the occurrence of an at least 20° C. temperaturedrop) of the lutetium-177 and EuK-Sub-kf-iodo-y-DOTAGA incorporationreaction.

Such a post-heating Formulation Composition may be an aqueouscomposition comprising one or more gentisate compounds and/or one ormore ascorbate compounds.

In certain aspects, following the lutetium-177 incorporation reaction,the produced ¹⁷⁷Lu-PSMA I&T may be first treated with one or moreascorbate compounds in the absence of a gentisate compound andsubsequent to such ascorbate compound treatment the ¹⁷⁷Lu-PSMA I&T maybe treated (e.g. admixed) with one or more gentisate compounds. In otheraspects, following the lutetium-177 incorporation reaction, the produced¹⁷⁷Lu-PSMA I&T may be treated substantially simultaneously with one ormore ascorbate compounds and one or more gentisate compounds. Forinstance, an aqueous formulation comprising both ascorbic acid or saltthereof or other ascorbate compound and gentisic acid or salt thereof orother gentisate compound may be added to the formed complex oflutetium-177 and EuK-Sub-kf-iodo-y-DOTAGA promptly after the terminationof the heating step.

The aqueous admixture of the ¹⁷⁷Lu-PSMA I&T and one or more gentisatecompounds and optionally one or more ascorbate compounds can be storeduntil administration to a patient.

As discussed, it has been found that such post-incorporation reactionuse of one or more ascorbate compounds can provide enhanced stabilityand shelf life of the ¹⁷⁷Lu-PSMA I&T. See, for instance, Examples 1 and2 which follow.

It has been further found that such post-incorporation reaction use ofone or more ascorbate compounds in combination with one or moregentisate compounds can provide enhanced stability and shelf life of the¹⁷⁷Lu-PSMA I&T. See, for instance, Examples 1 and which follow.

As referred to herein, an ascorbate compound or composition suitably mayinclude for example ascorbic acid and/or an ascorbate salt such assodium L-ascorbate, among others.

A gentisate compound or composition as referred to herein includes forexample gentisic acid (2,5-dihydroxybenzoic acid). The term gentisatecompound or composition also includes salts and esters of gentisic acid.A variety of gentisic acid salts may be suitably utilized as disclosedherein including for instance alkali metal, alkaline earth metal, andammonium salts. Sodium and potassium salts may be preferred in someaspects. Ester compounds also may be utilized in certain aspectsincluding for instance compounds esterified at one or both of thegentisic acid hydroxyl groups, such as compounds that have the2-hydroxyl and/or 5-hydroxyl moieties functionalized with a methylester, ethyl ester or other C₁₋₆alkyl esters. In at least certainaspects, preferred gentisate compounds or compositions include gentisicacid or a gentisic acid salt.

In another aspect, methods are provided for preparing ¹⁷⁷Lu-PSMA I&Tthat include admixing lutetium-177 and EuK-Sub-kf-iodo-y-DOTAGA; andheating the lutetium-177 and EuK-Sub-kf-iodo-y-DOTAGA admixture for lessthan 30 minutes, including 25 or 20 minutes or less. The lutetium-177and EuK-Sub-kf-iodo-y-DOTAGA admixture suitably can be heated for evenshorter periods such as up to or less than 18 minutes, or up to or lessthan 16, 15, 14, 13, 12, 11,10, 9 or 8 minutes. In general heating forbetween 5 and 12 minutes can be suitable, at temperatures that includeup to or less than 99 ° C., 98° C., 97° C., 96° C., 95° C., 94° C., 93°C., 92° C., 91° C. or 90° C. A reaction temperature of up to 40° C., 45°C., 50° C., 55° C., 60° C., 65° C., 70° C., 75° C., 80° C., 85° C., 90°C. or 95° C. may be suitable in certain aspects. Suitably, thelutetium-177 and EuK-Sub-kf-iodo-y-DOTAGA are heated as an aqueousmixture.

It has been found that such relatively mild reaction temperatures canprovide high levels (e.g., at least 98, 99, 99.5 or 99.8 mole percent)incorporation of lutetium-177 and the precursor compoundEuK-Sub-kf-iodo-y-DOTAGA (structures 1A and/or 1B above) together with areduced impurity profile. As noted, ¹⁷⁷Lu-PSMA I&T (structures 2A and/or2B above) is now provided for the first time at the high purities asdisclosed herein, including with the absence of prior impurities.

In preferred aspects, the incorporation of lutetium-177 andEuK-Sub-kf-iodo-y-DOTAGA includes at least one of the following 1), 2,3) or 4) and preferably at least 1) and 2), more preferably at least 1),2) and 3) and still more preferably each of the following 1), 2), 3) and4):

1) inclusion of one or more ascorbate compound in the lutetium-177incorporation reaction mixture. Optionally one or more gentisatecompounds also may be present in the lutetium-177 incorporation reactionmixture, but such inclusion of gentisate compound is less preferred asdiscussed. Thus, particularly preferred is inclusion of one or moreascorbate compound in the lutetium-177 incorporation reaction mixtureand without the inclusion of a gentisate compound;

2) a short heat treatment such up to or less than 30, 25, 20, 15, 12, 10or 8 minutes as described above;

3) heating temperatures of the incorporation reaction mixture such as upto or less than 40° C., 45° C., 50° C., 55° C., 60° C., 65° C., 70° C.,75° C., 80° C., 85° C., 90° C. or 95° C.; and 4) a post-heatingtreatment (addition) with one or more gentisate compounds and/or one ormore ascorbate compounds and preferably one or more gentisate compounds.Such treatments 1), 2), 3) and/or 4) can provide highly pure ¹⁷⁷Lu-PSMAI&T (structures 2A and/or 2B above) with notable absence of one or moreprior impurities together with high levels of lutetium-177incorporation. See, for instance, the results set forth in Example 1which follows.

In a further aspect, pharmaceutical compositions are provided. Preferredpharmaceutical compositions including aqueous formulations that comprisea complex of lutetium-177 and EuK-Sub-kf-iodo-y-DOTAGA (particularly¹⁷⁷Lu-PSMA I&T having an optical excess of structure 2A) in the highpurities as disclosed herein.

Preferred pharmaceutical compositions also may be aqueous compositionsthat include 1) a complex of lutetium-177 and EuK-Sub-kf-iodo-y-DOTAGA(particularly ¹⁷⁷Lu-PSMA I&T having an optical excess of structure 2A)and 2) one or more ascorbate compounds. In one aspect, suchpharmaceutical compositions may not contain any other stabilizercompounds. In other aspects, such pharmaceutical compositions maycontain one or more stabilizer compounds in addition to one or moreascorbate compounds.

Preferred pharmaceutical compositions also include aqueous compositionsthat include 1) a complex of lutetium-177 and EuK-Sub-kf-iodo-y-DOTAGA(particularly ¹⁷⁷Lu-PSMA I&T having an optical excess of structure 2A)and 2) i) one or more ascorbate compounds and ii) one or more gentisatecompounds.

The one or more ascorbate compounds may be suitably present in apharmaceutical composition in varying amounts, such as 5 or 10 mg/mL to120 mg/mL; or 30 mg/mL to 100 mg/mL; or 40 mg/mL to 80 or 90 mg/mL. In aparticular preferred aspect, the one or more ascorbate compounds such asan ascorbate salt may be present in an amount of 55 mg/mL to 75 mg/mL.

As discussed, the one or more ascorbate compounds may be incorporatedboth as a component of the lutetium-177 and EuK-Sub-kf-iodo-y-DOTAGAincorporation reaction as well as once the complex of lutetium-177 andEuK-Sub-kf-iodo-y-DOTAGA has been formed.

In such multiple additions to provide a desired amount of ascorbatecompound(s) in a final ¹⁷⁷Lu-PSMA I&T pharmaceutical composition, aReaction Composition may contain one or more ascorbate compounds such asascorbic acid and/or an ascorbate salt in an amount of 5 or 10 mg/mL to120 mg/mL; or 5 or 10 mg/mL to 100 or 110 mg/mL; or 5 or 10 mg/mL to 80or 90 mg/mL, in a particular preferred aspect, the one or more ascorbatecompounds such as ascorbic acid and/or an ascorbate salt may be presentin an amount of 55 mg/mL to 75 mg/mL.

Additionally, one or more ascorbate compounds such as ascorbic acidand/or an ascorbate salt may be added to a formed complex oflutetium-177 and EuK-Sub-kf-iodo-y-DOTAGA to provide a pharmaceuticalformulation containing that formed complex wherein a total amount ofascorbate compound(s) is for example 5 or 10 mg/mL to 100 mg/mL in theformulation; or 5 or 10 mg/mL to 60 or 80 mg/mL in the formulation; or 5or 10 mg/mL to 40 or 50 mg/mL in the formulation. In a particularpreferred aspect, the one or more ascorbate compounds such as ascorbicacid and/or an ascorbate salt may be present in an amount of 55 mg/mL to75 mg/mL in such formulation containing that formed complex oflutetium-177 and EuK-Sub-kf-iodo-y-DOTAGA. In a further preferredaspect, the one or more ascorbate compounds such as ascorbic acid and/oran ascorbate salt may be present in lower amounts of amount of 10 mg/mLor 15mg/mL to 20 mg/mL, 25 mg/mL, 30 mg/mL, 40 mg/mL, 45 mg/mL, 50mg/mL, or 55 mg/mL, in such formulation containing that formed complexof lutetium-177 and EuK-Sub-kf-iodo-y-DOTAGA. In certain preferredaspect, the one or more ascorbate compounds such as ascorbic acid and/oran ascorbate salt may be present in amounts up to 10 mg/mL, 15 mg/mL, 20mg/mL, 25 mg/mL, 30 mg/mL, 35 mg/mL, 40 mg/mL, 45 mg/mL, 50 mg/mL, 55mg/mL, 60 mg/mL, 65 mg/mL, 70 mg/mL, 75 mg/mL, 80 mg/mL, 85 mg/mL, 90mg/mL, 95 mg/mL or 100 mg/mL or more in such formulation containing thatformed complex of lutetium-177 and EuK-Sub-kf-iodo-y-DOTAGA.

In a pharmaceutical composition that contains a gentisate compound, oneor more gentisate compounds suitably may be present such as gentisicacid or a gentisate salt in an amount of for example 5 or 10 mg/mL to100 mg/mL; or 5 or 10 mg/mL to 60 or 80 mg/mL; or 5 or 10 mg/mL to 40 or50 mg/mL. In a particular preferred aspect, the one or more gentisatecompounds such as a gentisate salt may be present in an amount of 16mg/mL to 36 mg/mL. As discussed, such amounts of one or more gentisatecompounds may be preferably added to a formed complex of lutetium-177and EuK-Sub-kf-iodo-y-DOTAGA while or after heating, in the heating stepof the incorporation reaction, is reduced or terminated. As alsodiscussed, the one or more gentisate compounds may be preferably addedto a formed complex of lutetium-177 and EuK-Sub-kf-iodo-y-DOTAGA incombination with an ascorbate compound that is either already presentwith the complex of lutetium-177 and EuK-Sub-kf-iodo-y-DOTAGA , and/or acombination of a gentisate compound and an ascorbate compound are addedin combination to a formed complex of lutetium-177 andEuK-Sub-kf-iodo-y-DOTAGA. In certain preferred aspect, the one or moregentisate compounds such as gentisic acid may be present in amounts upto 1 mg/mL, 2 mg/mL, 3 mg/mL, 4 mg/mL, 5 mg/mL, 6 mg/mL, 7 mg/mL, 8mg/mL, 9 mg/mL, 10 mg/mL, 15 mg/mL, 20 mg/mL, 25 mg/mL, 30 mg/mL, 35mg/mL, 40 mg/mL, 45 mg/mL, 50 mg/mL, 55 mg/mL, 60 mg/mL, 65 mg/mL, 70mg/mL, 75 mg/mL, 80 mg/mL, 85 mg/mL, 90 mg/mL, 95 mg/mL or 100 mg/mL ormore, in such formulation containing that formed complex of lutetium-177and EuK-Sub-kf-iodo-y-DOTAGA.

In the present pharmaceutical compositions, a complex of lutetium-177and EuK-Sub-kf-iodo-y-DOTAGA (including, a compound of structure 2Aabove) also may be present in varying concentrations, such as to providea volumetric radioactivity of at least 100 MBq/mL, preferably of atleast 250, 300, 400, 500, 600, 700, 800, 900, 1000, 1200, 1400, 1600,1800 or 2000 MBq/mL for 0.5, 1, 2, 3, 4 or 5 days following preparationof the pharmaceutical composition.

In certain aspects, a pharmaceutical composition does not contain agentisate compound. In certain aspects, a pharmaceutical compositiondoes not contain any other stabilizer agent other than one or moreascorbate compounds. Preferably, the radiochemical purity of apharmaceutical composition is at least 95%, 96%, 97%, 98% or 99% for 3,4 or 5 days or more at a temperature of 30° C. or less followingpreparation of the composition. Even more preferably, the radiochemicalpurity of a pharmaceutical composition is at least 96%, 97% or 98% for3, 4 or 5 days or more at a temperature of 30° C. or less followingpreparation of the composition.

In a further aspect, a compound comprising a complex of lutetium-177 andEuK-Sub-kf-iodo-y-DOTAGA is provided, i.e. ¹⁷⁷Lu-PSMA I&T including¹⁷⁷Lu-PSMA I&T having an optical excess of structure 2A above, whereinthe complex is:

-   1) free of unchelated lutetium-177 in an amount of not more than 2,    1.5, 1.0 or 0.5 weight % based on total weight of the ¹⁷⁷Lu-PSMA    I&T, such as may be determined by radiometric detection (including    HPLC radiometric detection); and/or-   2) free of radiochemical impurities in an amount of not more than 5,    4, 3.5, 3, 2.5, 2, 1.5, 1.0 or 0.5 weight % based on total weight of    the ¹⁷⁷Lu-PSMA I&T, such as may be determined by radiometric    detection (including HPLC radiometric detection); and/or-   3) free of chemical impurities in an amount of not more than 5, 4,    3, 2, 1 or 0.5 weight %, all weight % based on total weight of the    ¹⁷⁷Lu-PSMA I&T, such as may be determined by HPLC/UV analysis, and    where the ¹⁷⁷Lu-PSMA I&T is maintained at 30° C. or less and such    purity levels are exhibited for 3, 4 or 5 days or more following    preparation of the ¹⁷⁷Lu-PSMA I&T.

In a yet further aspect, a compound comprising a complex of lutetium-177and EuK-Sub-kf-iodo-y-DOTAGA is provided, i.e. ¹⁷⁷Lu-PSMA I&T including¹⁷⁷Lu-PSMA I&T having an optical excess of structure 2A above, whereinthe complex is:

-   1) free of unchelated lutetium-177 in an amount of not more than 2,    1.5, 1.0 or 0.5 weight % based on total weight of the ¹⁷⁷Lu-PSMA    I&T, such as may be determined by radiometric detection (including    HPLC radiometric detection); and/or-   2) free of radiochemical impurities in an amount of not more than 5,    4, 3.5, 3, 2.5, 2, 1.5, 1.0 or 0.5 weight % based on total weight of    the ¹⁷⁷Lu-PSMA I&T, such as may be determined by radiometric    detection (including HPLC radiometric detection); and/or-   3) free of chemical impurities including a gentisate adduct impurity    in an amount of not more than 5, 4, 3, 2, 1 or 0.5 weight %, all    weight % based on total weight of the ¹⁷⁷Lu-PSMA I&T, such as may be    determined by HPLC/UV analysis, and where the ¹⁷⁷Lu-PSMA I&T is    maintained at 30° C. or less and such purity levels are exhibited    for 3, 4 or 5 days or more following preparation of the ¹⁷⁷Lu-PSMA    I&T.

Suitably, the compound may be present in an aqueous formulation. Asunderstood, a radiochemical impurity will contain lutetium-177 or adegradation species thereof, while a chemical impurity may or may notcontain lutetium-177 or a degradation species thereof. Amounts ofradiochemical and chemical impurities as referred to herein can beassessed by chromatography including HPLC.

In a still further aspects, ¹⁷⁷Lu-PSMA I&T (including structures 2Aand/or 2B above) is provided as obtainable by or obtained from a processdisclosed herein, including a process for the incorporation lutetium-177and EuK-Sub-kf-iodo-y-DOTAGA comprising at least one of the following1), 2) or 3) and preferably at least 1) and 2) and more preferably eachof the following 1), 2) and 3):

1) inclusion of one or more ascorbate compound in the lutetium-177incorporation reaction mixture. Optionally one or more gentisatecompounds also may be present in the lutetium-177 incorporation reactionmixture, but such inclusion of gentisate compound is less preferred asdiscussed. Thus, particularly preferred is inclusion of one or moreascorbate compound in the lutetium-177 incorporation reaction mixtureand without the inclusion of a gentisate compound;

2) a short heat treatment such up to or less than 30, 20, 15, 12, 10 or8 minutes as described above; and

3) a post-heating treatment (addition) with one or more gentisatecompounds and/or one or more ascorbate compounds and preferably one ormore gentisate compounds.

Methods of treatment are also provided including to treat a subject thatis suffering from a cell proliferative disease or disorder, particularlya cancer by administering to the subject an effective amount of¹⁷⁷Lu-PSMA I&T. In particular aspects, ¹⁷⁷Lu-PSMA I&T having an opticalexcess of structure 2A is administered.

In particular, the present ¹⁷⁷Lu-PSMA I&T and compositions, including¹⁷⁷Lu-PSMA I&T having an optical excess of structure 2A above, may beused to treat a subject suffering from prostate cancer, includingmetastatic castration-resistant prostate cancer (such as may bemanifested by progression of the disease despite prior surgical orchemical castration) including those subjects that have progressedfollowing treatment with androgen receptor-axis-targeted (ARAT)therapies.

In one aspect, methods for treating a patient such as a human sufferingfrom cancer, comprising: a) admixing 1) lutetium-177 and 2)EuK-Sub-kf-iodo-y-DOTAGA in the substantial or complete absence of agentisate compound; b) heating the admixed 1) lutetium-177 and 2)EuK-Sub-kf-iodo-y-DOTAGA in the substantial or complete absence of agentisate compound, wherein a complex of lutetium-177 andEuK-Sub-kf-iodo-y-DOTAGA is formed; and c) administering the complex oflutetium-177 and EuK-Sub-kf-iodo-y-DOTAGA to patient. Suitably, 1)lutetium-177, 2) EuK-Sub-kf-iodo-y-DOTAGA and 3) one or more stabilizercompounds are admixed in the absence of a gentisate compound.Suitably, 1) lutetium-177, 2) EuK-Sub-kf-iodo-y-DOTAGA and 3) one ormore stabilizer compounds are heated in the absence of a gentisatecompound.

Uses of the present complexes of lutetium-177 andEuK-Sub-kf-iodo-y-DOTAGA to treat a patient (such as human) sufferingfrom cancer are also provided, wherein the complex is obtained orobtainable from a) admixing 1) lutetium-177 and 2)EuK-Sub-kf-iodo-y-DOTAGA in the substantial or complete absence of agentisate compound; and b) heating the admixed 1) lutetium-177 and 2)EuK-Sub-kf-iodo-y-DOTAGA in the substantial or complete absence of agentisate compound, wherein a complex of lutetium-177 andEuK-Sub-kf-iodo-y-DOTAGA is formed. Suitably, 1) lutetium-177, 2)EuK-Sub-kf-iodo-y-DOTAGA and 3) one or more stabilizer compounds areadmixed in the absence of a gentisate compound. Suitably, 1)lutetium-177, 2) EuK-Sub-kf-iodo-y-DOTAGA and 3) one or more stabilizercompounds are heated in the absence of a gentisate compound.

In a further aspect, kits are provided for ¹⁷⁷Lu-PSMA I&T, includingcold kits where the ¹⁷⁷Lu-PSMA I&T can be prepared shortly beforeadministration such as in a medical facility, for example a hospitallaboratory or nuclear pharmacy. In such a kit, EuK-Sub-kf-iodo-y-DOTAGA(structures 1A and/or 1B) may be provided in a vial or other containerin lyophilized or other form separate from lutetium-177. TheEuK-Sub-kf-iodo-y-DOTAGA and lutetium-177 are reacted as disclosedherein at the medical facility to provide ¹⁷⁷Lu-PSMA I&T (including¹⁷⁷Lu-PSMA I&T having an optical excess of structure 2A) which then canbe promptly administered to a patient. Such kits including cold kits maycomprise components such as, for example, one or more buffering agentssuch as an acetate compound and/or one or more radioprotectants orstabilizer agents such as ascorbate compound and a gentisate compound.

In a yet further aspect, packaged preparations or products of ¹⁷⁷Lu-PSMAI&T (including ¹⁷⁷Lu-PSMA I&T having an optical excess of structure 2Aabove)) are provided. A packaged preparation may comprise 1) ¹⁷⁷Lu-PSMAI&T (including ¹⁷⁷Lu-PSMA I&T having an optical excess of structure 2A)and optionally 2) instructions for using ¹⁷⁷Lu-PSMA I&T (including¹⁷⁷Lu-PSMA I&T having an optical excess of structure 2A) for treating acancer such as prostate cancer. Preferably, the packaged preparationwill comprise a therapeutically effective amount of ¹⁷⁷Lu-PSMA I&T(including ¹⁷⁷Lu-PSMA I&T having an optical excess of structure 2A). Theinstructions suitably may be in written form, including as a packaginglabel. The ¹⁷⁷Lu-PSMA I&T (including ¹⁷⁷Lu-PSMA I&T having an opticalexcess of structure 2A) suitably may be contained within a lead vesselor other container that is within further packaging that may includeproduct identification, instructions for use or other information.

Other aspects of the invention are disclosed infra.

BRIEF DESCRIPTION OF FIGURES

FIG. 1A shows an exemplary reaction with acetate and gentisate (peak at10.2 min consistent with the gentisate adduct impurity always appears)−20 min reactions at 90° C. min as detailed in Example 1 which follows.

FIGS. 1A-1C show exemplary reactions with ascorbate and gentisate (peakat 10.2 min consistent with the gentisate adduct impurity appears) −20min reactions at 90° C. as detailed in Example 1 which follows.

FIG. 1D shows an exemplary reaction with just ascorbate (peak at −10.2min consistent with the gentisate adduct impurity never appears) −20 minreactions at 90° C. as detailed in Example 1 which follows.

FIGS. 1E and 1F show HPLC chromatograms of Example 2 which follows.

FIG. 2 shows schematically the general synthesis and formulationof¹⁷⁷Lu-PSMA I&T in Example 2 which follows.

DETAILED DESCRIPTION

In one aspect, new pharmaceutical compositions are provided thatcomprise: (a) a complex of lutetium-177 and EuK-Sub-kf-iodo-y-DOTAGA;and (b) one or more ascorbate compounds.

Preferably, the pharmaceutical composition is free of a gentisate adductimpurity.

Suitably, the pharmaceutical composition is an aqueous formulation.

In one embodiment, the pharmaceutical composition at least substantiallyfree of a gentisate compound. In another embodiment, the pharmaceuticalcomposition comprises one or more gentisate compounds. In a furtherembodiment, the pharmaceutical composition comprises one or morestabilizers in addition to one or more ascorbate compounds.

In a further aspect, new pharmaceutical compositions are provided thatcomprise (a) a complex of lutetium-177 and EuK-Sub-kf-iodo-y-DOTAGA; and(b) one or more stabilizer compounds, wherein the composition is atleast substantially free of a gentisate compound. Preferably, thepharmaceutical composition is an aqueous formulation. Suitably, the oneor more stabilizers comprise one or more ascorbate compounds. In oneembodiment, the pharmaceutical composition is at least substantiallyfree of a gentisate compound. In another embodiment, the pharmaceuticalcomposition comprises one or more gentisate compounds. In a furtherembodiment, the pharmaceutical composition comprises one or morestabilizers in addition to one or more ascorbate compounds.

In a further aspect, new pharmaceutical compositions are provided thatcomprise (a) a complex of lutetium-177 and EuK-Sub-kf-iodo-y-DOTAGA; (b)one or more stabilizer compounds, wherein the composition is at leastsubstantially free of a gentisate adduct impurity. As referred toherein, a pharmaceutical composition or complex of lutetium-177 andEuK-Sub-kf-iodo-y-DOTAGA is at least substantially free of a gentisateadduct impurity if an HPLC does not show the presence of a peak (e.g. byvisible review of spectra) being present in the 9 to 12 minute region ofan HPLC chromatogram corresponding, in particular aspects the 9 or 9.5to 10.5 or 11 minute region or the about 10.2 minute region asexemplified by the radio chromatograms of FIGS. 1C and 1D, as discussedabove.

Preferably, the pharmaceutical composition is an aqueous formulation.Suitably, the one or more stabilizers comprise one or more ascorbatecompounds. In one embodiment, the pharmaceutical composition is at leastsubstantially free of a gentisate compound. In another embodiment, thepharmaceutical composition comprises one or more gentisate compounds. Ina further embodiment, the pharmaceutical composition comprises one ormore stabilizers in addition to one or more ascorbate compounds.

In a preferred embodiment, in the above pharmaceutical compositions, thecomplex of lutetium-177 and EuK-Sub-kf-iodo-y-DOTAGA comprises inoptical excess the following structure:

In another preferred embodiment, in the above pharmaceuticalcompositions, the complex of lutetium-177 and EuK-Sub-kf-iodo-y-DOTAGAcomprises in optical excess the following structure:

Preferably, in the above pharmaceutical compositions, the complex oflutetium-177 and EuK-Sub-kf-iodo-y-DOTAGA is:

-   1) free of unchelated lutetium-177 in an amount of 1 weight % or    less; and/or-   2) free of radiochemical impurities in an amount of 3 weight % or    less; and/or-   3) free of chemical impurities in an amount of 5 weight % or less,-   all weight % based on total weight of the ¹⁷⁷Lu-PSMA I&T, and-   where complex is maintained at 30° C. or less and such purity levels    are exhibited for 3, 4 or 5 days or more following preparation of    the complex.

Preferably, in the above pharmaceutical compositions, a complex oflutetium-177 and EuK-Sub-kf-iodo-y-DOTAGA is present in atherapeutically effective amount, e.g., in a unit dosage or multipledosages as disclose herein.

Preferably, in the above pharmaceutical compositions, one or morestabilizer compounds such as one or more ascorbate compounds are presentin an effective amount in the pharmaceutical composition, for example toprovide stability and purity levels as disclosed herein, such as acomplex of lutetium-177 and EuK-Sub-kf-iodo-y-DOTAGA is present in atherapeutically effective amount, e.g., in a unit dosage or multipledosages as disclose herein, such as where a composition maintained at30° C. or less desired purity levels are exhibited for 3, 4 or 5 days ormore following preparation of the complex of lutetium-177 andEuK-Sub-kf-iodo-y-DOTAGA. The exemplary stabilizer compound amountsdisclosed herein are preferred in certain aspects.

In certain aspects, in the above pharmaceutical compositions, andmethods disclosed herein, an optical excess of a complex of lutetium-177and EuK-Sub-kf-iodo-y-DOTAGA present or utilized such as an opticalexcess of a compound of structure 2A above or an optical excess of acompound of structure 2B above. In additional certain aspects, the abovepharmaceutical compositions, and methods disclosed herein, a substantialoptical excess of a complex of lutetium-177 and EuK-Sub-kf-iodo-y-DOTAGAis present or utilized such as a substantial optical excess of acompound of structure 2A above or a substantial optical excess of acompound of structure 2B above.

In further aspects, methods for preparing ¹⁷⁷Lu-PSMA I&T are providedthat comprise: a) admixing 1) lutetium-177 and 2)EuK-Sub-kf-iodo-y-DOTAGA; and b) heating the admixed 1) lutetium-177 and2) EuK-Sub-kf-iodo-y-DOTAGA for 15 minutes or less; wherein a complex oflutetium-177 and EuK-Sub-kf-iodo-y-DOTAGA is formed.

Preferably the admixed 1) lutetium-177 and 2) EuK-Sub-kf-iodo-y-DOTAGAare at least substantially free of a gentisate compound during the b)heating. Preferably, one or more ascorbate compounds are admixed withthe 1) lutetium-177 and 2) EuK-Sub-kf-iodo-y-DOTAGA.

In further preferred aspects, the methods may further comprise addingone or more gentisate compounds to the complex of lutetium-177 andEuK-Sub-kf-iodo-y-DOTAGA, for example where such one more ascorbatecompounds are added upon reduction or termination of heat.

In still further preferred aspects, the methods may further compriseadding one or more gentisate compounds and/or one or more ascorbatecompounds to the complex of lutetium-177 and EuK-Sub-kf-iodo-y-DOTAGA,for example where such one or more gentisate compounds and/or one ormore ascorbate compounds are added upon reduction or termination ofheat.

Methods are also provided for preparing ¹⁷⁷Lu-PSMA I&T, comprising a)admixing 1) lutetium-177 and 2) EuK-Sub-kf-iodo-y-DOTAGA; b) heating theadmixed 1) lutetium-177 and 2) EuK-Sub-kf-iodo-y-DOTAGA, wherein acomplex of lutetium-177 and EuK-Sub-kf-iodo-y-DOTAGA is formed; and c)adding one or more ascorbate compounds while or after the heating isreduced or terminated. In certain aspects, both 1) a gentisate compoundand 2) an ascorbate compound are added while or after the heating isreduced or terminated. Suitably, an admixture of 1) lutetium-177, 2)EuK-Sub-kf-iodo-y-DOTAGA, and 3) one or more stabilizers are heated,wherein a complex of lutetium-177 and EuK-Sub-kf-iodo-y-DOTAGA isformed.

¹⁷⁷Lu-PSMA I&T is a lutetium-177 complex of the above structures 1Aand/or 1B and may be represented by the following structures 2A and/or2B:

¹⁷⁷Lu-PSMA I&T also has a chemical name ofsuber-1-oyl-ε-(DOTA-GA-3-iodo-D-Tyr-D-Phe-D-Lys-OH)-8-oyl-E-(HO-Glu-ureido-Lys-OH);lutetium-177(3⁺). ¹⁷⁷Lu-PSMA I&T has a molecular formula of C₆₃H₈₉¹⁷⁷LuIN₁₁O₂ and molecular mass of 1672.29 g/mol.

The present invention, including compounds, methods, and pharmaceuticalcompositions/formulations will be described with reference to thefollowing definitions which, for convenience, are set forth below.Unless otherwise specified, the below terms used herein are defined asfollows:

I. Definitions

As used herein, the term “a,” “an,” “the” and similar terms used in thecontext of the present invention (especially in the context of theclaims) are to be construed to cover both the singular and plural unlessotherwise indicated herein or clearly contradicted by the context.

The language “and/or” is used herein as a shorthand notation torepresent the expression “and,” describing the combination of items, aswell as “or,” describing the items in the alternative form.

Unless otherwise stated, structures depicted herein are also meant toinclude all stereochemical forms of the structure; i.e., the R and Sconfigurations for each asymmetric center. Therefore, singlestereochemical isomers as well as enantiomeric and diastereomericmixtures of the present compounds are within the scope of the invention.

The term “about”, as used herein, means an acceptable margin of errorfor a particular value, which depends in part on how the value ismeasured or determined. In certain embodiments, “about” as used hereinwill be understood by persons of ordinary skill in the art to mean up toplus or minus 20% of the particular term. In further embodiments,“about” as used herein will be understood by persons of ordinary skillin the art to mean up to plus or minus 10% of the particular term.

As used herein, the term “optically enriched” or “optical excess”denotes the presence of one or more non-racemic stereoisomeric centersin a molecule, wherein the configuration of at least one stereoisomericcenter has a predominance of one stereoisomeric configuration (R or S).For example, one stereoisomeric center in a molecule, typically a carbonatom, may have greater than 50 or 55 weight % (based on total weight ofthe compound) of its attached atoms spatially arranged in the (R)configuration. Alternatively, more than 50 weight % (based on totalweight of the compound) may be spatially arranged in the (S)configuration. More preferably the molecule, or its stereoisomericcenter, is substantially optically enriched, and even more preferably issubstantially enantiomerically pure.

As used herein, the term “substantially optically enriched” or“substantial optical excess”, when referring to a stereoisomer orstereoisomeric center, denotes that at least about 60 weight % (based ontotal weight of the compound), preferably about 70 weight % (based ontotal weight of the compound), more preferably about 80 weight % (basedon total weight of the compound), still more preferably about 90 weight% (based on total weight of the compound) of one stereoisomer or onestereoisomeric center configuration predominates in the mixture, with atleast about 95 weight % (based on total weight of the compound) of onestereoisomer or one stereoisomeric center configuration being even morepreferred. In some preferred embodiments, the compound is “substantiallyenantiomerically pure”, that is, at least about 97.5 weight % (based ontotal weight of the compound), more preferably about 99 weight % (basedon total weight of the compound), even more preferably about 99.5 weight% (based on total weight of the compound) of one stereoisomericconfiguration predominates.

As used herein, the term “substantially pure” means sufficientlyhomogeneous to appear free of readily detectable impurities asdetermined by standard analytical methods, such as thin layerchromatography (TLC), gel electrophoresis, high performance liquidchromatography (HPLC), nuclear magnetic resonance (NMR), and massspectrometry (MS); or sufficiently pure such that further purificationwould not detectably alter the physical and chemical properties, orbiological and pharmacological properties, such as enzymatic andbiological activities, of the substance. In certain embodiments,“substantially pure” refers to a collection of molecules, wherein atleast about 55%, about 60%, about 65%, about 70%, about 75%, about 80%,about 85%, about 90%, about 95%, about 97%, about 98%, about 98.5%,about 99%, about 99.5% or about 99.9% or greater of the molecules are asingle compound, including a racemic mixture or a single stereoisomerthereof, as determined by standard analytical methods.

As used herein, and unless otherwise specified, the terms “treat,”“treating” and “treatment” refer to the eradication or amelioration of adisease, disorder, or condition, or of one or more symptoms associatedwith the disease, disorder or condition. In certain embodiments, theterms refer to minimizing the advancement or worsening of the disease,disorder, or condition resulting from the administration of aformulation of the invention to a patient with such a disease, disorder,or condition. In some embodiments, the terms refer to the administrationof a formulation provided herein, after the onset of symptoms of theparticular disease, disorder, or condition. The terms “treat,”“treating”, “treatment”, or the like, as used herein covers thetreatment of a disease, disorder, or condition in a subject, e.g., amammal, and includes at least one of: (i) inhibiting the disease,disorder, or condition, i.e., partially or completely halting itsprogression; (ii) relieving the disease, disorder, or condition, i.e.causing regression of symptoms of the disease, disorder, or condition,or ameliorating a symptom of the disease, disorder, or condition; and(iii) reversal or regression of the disease, disorder, or condition,preferably eliminating or curing of the disease, disorder, or condition.In a particular embodiment the terms “treat,” “treating”, “treatment”,or the like, covers the treatment of a disease, disorder, or conditionin a mammal, e.g., a primate, e.g., a human, and includes at least oneof (i), (ii), and (iii) above. As is known in the art, adjustments forage, body weight, general health, sex, diet, time of administration,drug interaction and the severity of the condition may be necessary, andwill be ascertainable with routine experimentation by one of ordinaryskill in the art based on the invention described herein.

As used herein, the terms “subject”, and “patient” are usedinterchangeably. The terms “subject” and “patient” refer to an animalsuch as a mammal including non-primates (e.g., a cow, pig, horse, sheep,rabbit, guinea pig, rat, cat, dog, and mouse) and primates (e.g., amonkey, chimpanzee and a human). In a particular embodiment, the subjectis a human.

Syntheses

¹⁷⁷Lu-PSMA I&T (including structures 2A and/or 2B below) can be preparedby complexing or incorporating ¹⁷⁷Lu (lutetium-177) or halide thereofsuch as ¹⁷⁷LuCl₃ with EuK-Sub-kf-iodo-y-DOTAGA (structures 1A and/or 1Bbelow).

An IUPAC designation of structure 2A is lutetate(5-)-177Lu,[N-[(4R)-4-(carboxy-KO)-4-[4,7,10-tris[(carboxy-KO)methyl]-1,4,7,10-tetraazacyclododec-1-yl-KN1,KN4,KN7,KN10]-1-oxobutyl]-3-iodo-D-tyrosyl-D-phenylalanyl-N6-[8-[[(5S)-5-carboxy-5-[[[[(1S)-1,3-dicarboxypropyl]amino]carbonyl]amino]pentyl]amino]-1,8-dioxooctyl]-D-lysinato(8-)]-,hydrogen (1:5).

An IUPAC designation of compound 2B islutetate(5-)-177Lu,N-[(4S)-4-(carboxy-KO)-4-[4,7,10-tris[(carboxy-KO)methyl]-1,4,7,10-tetraazacyclododec-1-yl-KN1,KN4,KN7,KN10]-1-oxobutyl]-3-iodo-D-tyrosyl-D-phenylalanyl-N6-[8-[[(5S)-5-carboxy-5-[[[[(1S)-1,3-dicarboxypropyl]amino]carbonyl]amino]pentyl]amino]-1,8-dioxooctyl]-D-lysinato(8-)]-,hydrogen (1:5).

The R isomer compound of structure 1A has an IUPAC name ofN-[(4R)-4-(carboxy-KO)-4-[4,7,10-tris[(carboxy-KO)methyl]-1,4,7,10-tetraazacyclododec-1-yl-KN1,KN4,KN7,KN10]-1-oxobutyl]-3-iodo-D-tyrosyl-D-phenylalanyl-N6-[8-[[(5S)-5-carboxy-5-[[[[(1S)-1,3-dicarboxypropyl]amino]carbonyl]amino]pentyl]amino]-1,8-dioxooctyl]-D-lysinato(8-)]-,hydrogen (1:5)).

The S isomer compound of structure 1B has an IUPAC name of:[N-[(4S)-4-(carboxy-KO)-4-[4,7,10-tris[(carboxy-KO)methyl]-1,4,7,10-tetraazacyclododec-1-yl-KN1,KN4,KN7,KN10]-1-oxobutyl]-3-iodo-D-tyrosyl-D-phenylalanyl-N6-[8-[[(5S)-5-carboxy-5-[[[[(1S)-1,3-dicarboxypropyl]amino]carbonyl]amino]pentyl]amino]-1,8-dioxooctyl]-D-lysinato(8-)]-,hydrogen (1:5)).

The structures 1A and/or 1B may be suitably formed as describedpreviously such as in Weineisen et al. J Nucl Med 2015; 56:1169-1176;and Chatalic, Theranostics, 6(6), 849-861 (2016). To provide anoptically enriched or substantially optically enriched orenantiomerically pure sample of ¹⁷⁷Lu-PSMA I&T the corresponding opticalisomer of EuK-Sub-kf-iodo-y-DOTAGA may be used in the incorporationreaction. That is, the compound of structure 1A may be reacted withlutetium-177 to provide the R isomer complex of structure 2A, and thecompound of structure 1B may be reacted with lutetium-177 to provide theS isomer complex of structure 2B. The structures 1A and/or 1B also areavailable from piCHEM (RaabaGrambach, Austria). Optically enrichedmixtures of structures 1A and/or 1B suitably may be prepared with use ofan optically enriched precursor (reagent) and/or separation of opticalisomers with an appropriate optically active reagent such as anoptically active salt.

It is understood that ¹⁷⁷Lu-PSMA I&T as referred to herein includes theabove structures 2A and/or 2B as well as other complexes of lutetium(¹⁷⁷Lu) and EuK-Sub-kf-iodo-y-DOTAGA. For instance, references herein to¹⁷⁷Lu-PSMA I&T include compounds that generally correspond to structure2A and/or 2B but where the ¹⁷⁷Lu substantially complexes to otherportions or moieties (such as one or more other nitrogens) of theEuK-Sub-kf-iodo-y-DOTAGA molecule than as depicted in structures 2A and2B above. References to ¹⁷⁷Lu-PSMA I&T also may include otherstereoisomers than those shown in structures 1A, 1B, 2A, and 2B above,although the stereoisomers depicted in structures 1A, 1B, 2A, and 2B arepreferred, particularly structures 1A and 2A.

To synthesize ¹⁷⁷Lu-PSMA I&T, lutetium-177 (¹⁷⁷Lu) can be admixed withEuK-Sub-kf-iodo-y-DOTAGA. The ¹⁷⁷Lu suitably may be carrier added ormore preferably no-carrier-added (n.c.a.) lutetium-177. To facilitateincorporation (e.g. complexing including chelating) of lutetium-177 withthe EuK-Sub-kf-iodo-y-DOTAGA compound, preferably an admixture of thecompounds is thermally treated.

As discussed, it has been found that substantially completeincorporation of lutetium-177 and EuK-Sub-kf-iodo-y-DOTAGA can beaccomplished under comparatively mild conditions including relativelyshort heating times such as up to or less than 30, 25, 20, 15, 12, 10,9, 8, 7, 6 or 5 minutes and/or reduced temperatures such as up to orless than 99° C., 98° C., 97° C., 96° C., 95° C., 94° C., 93° C., 92°C., 91° C. or 90° C., or even lower temperatures for the incorporationreaction such as up to or less than 95° C., 90° C., 85° C., 80° C., 75°C., 70° C., 65° C., 60° C., 55° C., 50° C., 45° C. or 40° C. includingfor relatively short heating times such as up to or less than 30, 25,20, 15, 12, 10 or 8 minutes.

In some embodiments, an admixture of lutetium-177 andEuK-Sub-kf-iodo-y-DOTAGA is heated for 20 minutes of less. In certainpreferred embodiments, the admixture is heated for 15 minutes of less.In certain preferred embodiments, the admixture is heated for 12 minutesof less. In certain preferred embodiments, the admixture is heated forbetween about 8 and 12 minutes. For example, the admixture is heated forup to or less than about 8 minutes, for up to or less than about 9minutes, for up to or less than about 10 minutes, for up to or less thanabout 11 minutes, or for up to or less than about 12 minutes. In certainpreferred embodiments, the admixture is heated for at least about 8, 9,10, 11 or 12 minutes.

In some embodiments, an admixture of lutetium-177 andEuK-Sub-kf-iodo-y-DOTAGA is heated at about 98° C. or less. In certainpreferred embodiments, the admixture is heated at about 90° C.±5° C. Forexample, the admixture is heated at about 85° C., at about 86° C., atabout 87° C., at about 88° C., at about 89° C., at about 90° C., atabout 91° C., at about 92° C., at about 93° C., at about 94° C., or atabout 95° C. Lower temperatures for the lutetium-177 incorporation alsomay be employed such as up to or less than 95° C., 90° C., 85° C., 80°C., 75° C., 70° C., 65° C., 60° C., 55° C., 50° C., 45° C. or 40° C.including as discussed above for relatively short heating times such asup to or less than 30, 25, 20, 15, 12, 10 or 8 minutes.

In some embodiments, a formulation including EuK-Sub-kf-iodo-y-DOTAGAand one or more ascorbate compounds is admixed with lutetium-177. Incertain preferred embodiments, an acidic aqueous formulation oflutetium-177 is admixed with EuK-Sub-kf-iodo-y-DOTAGA and one or moreascorbate compounds (a Reaction Composition comprising one or moreascorbate compounds).

As referred to herein, an ascorbate compound suitably may include forexample ascorbic acid or an ascorbate salt such as sodium L-ascorbate,among others.

In certain preferred embodiments, a hydrogen halide or acid halideaqueous formulation of lutetium-177 is admixed withEuK-Sub-kf-iodo-y-DOTAGA, including together with one more ascorbatecompounds. In certain preferred embodiments, a hydrochloride acidaqueous formulation of lutetium-177 is admixed withEuK-Sub-kf-iodo-y-DOTAGA, including with one or more ascorbatecompounds.

It is generally preferred that admixture of lutetium-177 andEuK-Sub-kf-iodo-y-DOTAGA is agitated during heat treatment, for examplethe admixture is stirred or shaken during a portion or substantially allof the heat treatment.

In some embodiments, the produced complex of lutetium-177 andEuK-Sub-kf-iodo-y-DOTAGA does not contain a gentisate adduct impuritythat has a retention time of the 9 to 12 minute region, in particularaspects the 9 or 9.5 to 10.5 or 11 minute region or the about 10.2minute region as shown in the spectra of FIGS. 1C and 1D and by HPLCanalysis as defined herein, i.e. high-performance liquid chromatographywith a Waters) (Bridge BEH Phenyl-Hexyl Column, 130 Å, 3.5 μm, 4.6mm×150 mm using 0.1% trifluoracetic acid in water (Mobile Phase A) and0.1% trifluoracetic acid in acetonitrile (Mobile Phase B), with a lineargradient from 85% Mobile Phase A to 55% Mobile Phase A being used over12 minutes and the ratio was held for 15 minutes.

In some embodiments, the incorporation of lutetium-177 andEuK-Sub-kf-iodo-y-DOTAGA is greater than 98 mole percent. In certainpreferred embodiments, the molar incorporation of lutetium-177 andEuK-Sub-kf-iodo-y-DOTAGA is greater than 99 mole percent, including99.5, 99.6, 99.7, 99.8 and 99.9 mole percent.

In some embodiments, the radiochemical purity of the complex oflutetium-177 and EuK-Sub-kf-iodo-y-DOTAGA formulated as disclosed hereinwith one or more ascorbate compounds and optionally with one or moregentisate compounds is at least or up to 95%, 96%, 97% or 98% for 3, 4or 5 days or more following the incorporation reaction and subsequentformulation with ascorbate compound(s) and optional gentisatecompound(s) with storage of the ¹⁷⁷Lu-PSMA I&T at a temperature of 30°C. or less.

Such levels of radiochemical purity and incorporation of lutetium-177and EuK-Sub-kf-iodo-y-DOTAGA can be provided by the reaction product ofthe syntheses disclosed herein and formulation of such reaction productwith one or more ascorbate compounds and optionally one or moregentisate compounds without further treatment (particularlypurification) step such as chromatography. Thus, significantly, theformulated lutetium-177 incorporation reaction admixture can be directlypackaged (for example, stored in a sealed vial or IV bag) followingformulation of the incorporation reaction product with such high purity¹⁷⁷Lu-PSMA I&T without the need for a purification or other treatmentstep to remove impurities.

If desired however ¹⁷⁷Lu-PSMA I&T prepared as disclosed herein may befurther treated following incorporation of lutetium-177 andEuK-Sub-kf-iodo-y-DOTAGA, for example through HPLC or otherchromatography or other purification treatment.

Preferred preparations of ¹⁷⁷Lu-PSMA I&T may include one or more andpreferably each of the following steps 1-6:

1. Provide lutetium-177 such as in a vial that can serve as a reactionvessel. The lutetium-177 suitably may be present in an aqueous acidicformulation, such as an HCl formulation.

2. Admix EuK-Sub-kf-iodo-y-DOTAGA with an aqueous buffer composition(Reaction Composition) that contains one or more ascorbate compound suchas one or more of sodium L-ascorbate and ascorbic acid.

3. Admix the EuK-Sub-kf-iodo-y-DOTAGA composition from step 2 with thelutetium-177 formulation of step 1. For example, theEuK-Sub-kf-iodo-y-DOTAGA composition can be added to a vial thatcontains the lutetium-177.

4. The admixture of step 3 containing EuK-Sub-kf-iodo-y-DOTAGA andlutetium-177 then can be heated preferably with agitation, for exampleshaking with heating at 40-99° C. or 70-99° C., or 80-98° C. for up to5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 or 20 minutes.Lower heating temperatures may be preferred, such as up to 40° C., 50°C., 60° C., 70° C., 80° C., 90° C. or 95° C. for up to 6, 7, 8, 9, 10,11, 12, 13, 14, 15, 16, 17, 18, 19 or 20 minutes.

5. At the end of the heating treatment of step 4, an aqueous composition(Formulation Composition) containing one or more ascorbate compoundsand, in certain systems, one or more gentisate compounds, is added tothe vial or other reaction vessel. For instance, within about 0.1, 0.25,0.5, 1, 2, 3, 4 or 5 minutes after commencing reduction or terminationof heating, an aqueous composition (Formulation Composition) containingone or more ascorbate compound is added to the vial or other reactionvessel. Reduction or termination of heating can include physical removalof the heating source from the reaction vessel, or termination of powerto the heating element.

6. The admixture of step 5 then may be transferred to a vesselcontaining an aqueous composition that comprises one or more ascorbatecompounds and, in certain systems, one or more gentisate compounds. Themixture may be filtered and transferred to a container such as asyringe, vial or IV bag. Desired dosages can be dispensed foradministration to a patient preferably within 5, 4, or 3 days fromcompleting step 5 above.

Pharmaceutical Compositions

In a further aspect, pharmaceutical compositions are provided. Preferredpharmaceutical compositions may include an aqueous compositionincluding 1) a complex of lutetium-177 and EuK-Sub-kf-iodo-y-DOTAGA and2) one or more ascorbate compounds. Particularly preferredpharmaceutical compositions may include an aqueous compositionincluding 1) a complex of lutetium-177 and EuK-Sub-kf-iodo-y-DOTAGA and2) one or more ascorbate compounds. Preferably, the radiochemical purityof the composition is at least 95%, 96%, 97%, 95% or 99% where thecomposition is maintained at 30° C. or less and for 3, 4 or 5 days ormore following preparation of the composition.

In certain preferred embodiments, the pharmaceutical composition is freeof unchelated lutetium-177 in an amount of not more than 2, 1.5, 1.0 or0.5 weight % based on total weight of the pharmaceutical composition,such as may be determined by radiometric detection (including HPLCradiometric detection), where the composition is maintained at 30° C. orless and such purity levels are exhibited for 3, 4 or 5 days or morefollowing preparation of the composition.

In additional preferred embodiments, the pharmaceutical composition isfree of radiochemical impurities in an amount of not more than 5, 4,3.5, 3, 2.5, 2, 1.5, 1 or 0.5 weight% based on total weight of thepharmaceutical composition, such as may be determined by radiometricdetection (including HPLC radiometric detection), where the compositionis maintained at 30° C. or less and such purity levels are exhibited for3, 4 or 5 days or more following preparation of the composition.

In yet still additional preferred embodiments, the pharmaceuticalcomposition is free of chemical impurities in an amount of not more than5, 4, 3, 2, 1 or 0.5 weight % based on total weight of thepharmaceutical composition, such as may be determined by chromatographyor other method including HPLC or HPLC/UV analysis, where thecomposition is maintained at 30° C. or less and such purity levels areexhibited for 3, 4 or 5 days or more following preparation of thecomposition.

In yet still additional preferred embodiments, the pharmaceuticalcomposition is 1) free of unchelated lutetium-177 in an amount of notmore than 2, 1.5, 1.0 or 0.5 weight % (such as may be determined byradiometric detection (including HPLC radiometric detection)); 2) freeof radiochemical impurities in an amount of not more than 5, 4, 3.5, 3,2.5, 2, 1.5, 1 or 0.5 weight% (such as may be determined by radiometricdetection (including HPLC radiometric detection); and 3) free ofchemical impurities in an amount of not more than 5, 4, 3, 2, 1 or 0.5weight % (such as may be determined by HPLC/UV analysis), with allweight % based on total weight of the pharmaceutical composition, andwhere the composition is maintained at 30° C. or less and such puritylevels are exhibited for 3, 4 or 5 days or more following preparation ofthe composition.

In certain embodiments, the pharmaceutical composition is formulated forparenteral administration, such as intravenous, intramuscular,intradermal, subcutaneous, intrathecal or intraperitonealadministration. For example, the pharmaceutical composition isformulated for intravenous, intramuscular, subcutaneous or intradermalinjection. In preferred aspects, the pharmaceutical composition isformulated for intravenous administration. In typical embodiments, thepharmaceutical composition may be administered in a form of apharmaceutical aqueous solution.

In certain embodiments, the pharmaceutical composition is an aqueoussolution, dispersion or other admixture such as for injection andcomprises ¹⁷⁷Lu-PSMA I&T (including ¹⁷⁷Lu-PSMA I&T having an opticalexcess of structure 2A) and preferably one or more ascorbate compounds.In further preferred embodiments, the pharmaceutical composition is anaqueous solution, dispersion or other admixture such as for injectionand comprises 1) ¹⁷⁷Lu-PSMA I&T including ¹⁷⁷Lu-PSMA I&T having anoptical excess of structure 2A) and preferably one or more ascorbatecompounds and one or more gentisate compounds.

In certain preferred embodiments, a pharmaceutical aqueous solution,dispersion or admixture is provided that includes: 1) a complex oflutetium-177 and EuK-Sub-kf-iodo-y-DOTAGA; and 2) at least onestabilizer compound that preferably can inhibit radiolytic degradationof the composition during storage following preparation of the complex.¹⁷⁷Lu-PSMA I&T is suitably present in a concentration that it provides avolumetric radioactivity of at least 100 MBq/mL, preferably of at least250, 500, 750 or 1000 MBq/mL within 1, 2, 3, 4 or 5 days followingpreparation. In certain aspects, ¹⁷⁷Lu-PSMA I&T is present in aconcentration that it provides a volumetric radioactivity of from 100 to1000 MBq/mL, preferably from or up to about 250, 500, 750 or 1000 MBq/mLwithin 1, 2, 3, 4 or 5 days following preparation.

In certain aspects, the one or more stabilizer compounds may be presentin a total concentration of at least 5 mg/mL, preferably at least 10mg/mL of an aqueous pharmaceutical composition.

In certain aspects, the one or more stabilizer compounds are one or moreof gentisic acid (2,5-dihydroxybenzoic acid) or salts thereof, ascorbicacid (L-ascorbic acid) or salts thereof (e.g. sodium ascorbate),methionine, histidine, melatonine, N-acetylmethionine, ethanol, orSe-methionine, preferably ascorbic acid or salts thereof and gentisicacid or salts thereof.

In certain aspects, the pharmaceutical aqueous formulation has a shelflife of at least 24 hours at about 30° C. or less, at least 48 hours atabout 30° C. or less, at least 72 hours at 30° C. or less, or from 24hours to 120 hours at 30° C. or less, from 24 hours to 96 hours at 30°C. or less, from 24 hours to 84 hours at 30° C. or less, from 24 hoursto 72 hours at 30° C. or less, in particular a shelf life of at least 72hours at 30° C. or less. In further particular aspects, thepharmaceutical aqueous formulation has a shelf life of at least 96 hours(or 4 days) at about 30° C. or less, or the pharmaceutical aqueousformulation has a shelf life of at least 120 hours (or 5 days) at about30° C. or less, or the pharmaceutical aqueous formulation has a shelflife of at least 144 hours (or 6 days) at about 30° C. or less.

In certain aspects, one, two or three total distinct stabilizercompounds are present during the complex formation of lutetium-177 andEuK-Sub-kf-iodo-y-DOTAGA, preferably in an amount to result in aconcentration of from 5 mg/mL or more of the 1-3 stabilizer compounds.As discussed, preferably at least one of the stabilizer compounds willbe an ascorbate compound.

In certain aspects, as discussed, one or more stabilizer compounds maybe added after formation of the complex of lutetium-177 andEuK-Sub-kf-iodo-y-DOTAGA, for example upon completion of heating of anadmixture of lutetium-177 and EuK-Sub-kf-iodo-y-DOTAGA. As discussed,preferably at least one of the stabilizer compounds added afterformation of ¹⁷⁷Lu-PSMA I&T will be an ascorbate compound, for examplewhere such stabilizer compound(s) are added upon temperaturereduction/termination at the conclusion of a heating step. In certainaspects, a gentisate compound also will be added after formation of¹⁷⁷Lu-PSMA I&T, for example where such stabilizer compound(s) are addedupon temperature reduction/termination at the conclusion of a heatingstep. As discussed, reduction or termination of temperature or heatingcan include physical removal of the heating source from the reactionvessel, or termination of power to the heating element.

In certain embodiments, a pharmaceutical aqueous solution may furtherinclude a sequestering agent, for example added after formation of acomplex lutetium-177 and EuK-Sub-kf-iodo-y-DOTAGA, suitably to removeuncomplexed lutetium-177. Suitable sequestering agents may include forexample diethylentriaminepentaacetic acid (DTPA) or a salt thereof,suitably in an amount to result in a concentration of from 0.01 to 0.50mg/mL of the aqueous ¹⁷⁷Lu-PSMA I&T composition.

In a particularly preferred aspect, ¹⁷⁷Lu-PSMA I&T is provided as asterile solution for intravenous use. The ¹⁷⁷Lu-PSMA I&T solutionsuitably may be clear, colorless to slightly yellow. A single-dose vialsuitably will contain 6.8 +/−10% GBq¹⁷⁷Lu-PSMA I&T for examplecalibrated at 1, 2, 3, 4, 5 or 6 or more days post-day of manufacture in10 to 14 mL formulated with one or more radioprotectants and may includea buffer. The pH range of the solution is preferably 5.0 to 7.0. Asdiscussed, radioprotectants or stabilizers may be one or more ascorbatecompounds and optionally together with one or more gentisate compounds.The ¹⁷⁷Lu-PSMA I&T also may be provided in a multi-dose format orpackaging, such as a multi-dose vial that contains multiple doses, suchas 2, 3, 4, 5, 6, 7, 8, 9, or 10 or more doses of ¹⁷⁷Lu-PSMA I&T.

Methods of Treatment

As discussed, use of ¹⁷⁷Lu-PSMA I&T (including structures 2A and/or 2Babove) is provided to treat cancers, including prostate cancer, forexample non-metastatic prostate cancer and metastatic prostate cancer,including hormone sensitive prostate cancer, castration resistantprostate cancer (CRPC) and drug-resistant prostate cancer, such asanti-androgen drug (e.g., enzalutamide) resistant prostate cancer.

In such methods, ¹⁷⁷Lu-PSMA I&T (including structures 2A and/or 2Babove) can be administered to a subject such as a human in an amounteffective to treat the cancer (e.g., reduction of tumor size), such asat a dose of about 0.1 GBq to about 30 GBq be suitably administered froma unit dose in a vial or a syringe or as a bulk solution in a vial or asyringe prepared from a cold-kit prepared with lutuetium-177 at a localor central nuclear pharmacy or through cGMP central manufacturing.

In certain embodiments, the subject is suffering from prostate cancersuch as one or more of castration-sensitive prostate cancer,castration-resistant prostate cancer, metastatic castration-resistantprostate cancer, advanced stage prostate cancer, drug-resistant prostatecancer such as anti-androgen-resistant prostate cancer (e.g.,enzalutamide-resistant prostate cancer, abiraterone-resistant prostatecancer, bicalutamide-resistant prostate cancer), docetaxel-resistantprostate cancer, PARP resistant prostate cancer, radium chlorideresistant prostate cancer, AR-V7-induced drug-resistant prostate cancersuch as AR-V7-induced enzalutamide-resistant prostate cancer,AKR1C3-induced drug-resistant prostate cancer such as AKR1C3-inducedenzalutamide-resistant prostate cancer, and combinations thereof.

In particular embodiments, the subject is a human suffering metastaticcastration-resistant prostate cancer and an effective amount of¹⁷⁷Lu-PSMA I&T (including ¹⁷⁷Lu-PSMA I&T having an optical excess ofstructure 2A) is administered to the subject to treat the prostatecancer.

In additional particular embodiments, the subject is a human sufferingoligometastatic hormone sensitive prostate cancer and an effectiveamount of ¹⁷⁷Lu-PSMA I&T (including ¹⁷⁷Lu-PSMA I&T having an opticalexcess of structure 2A) is administered to the subject to treat theprostate cancer.

In further particular embodiments, the subject is a human sufferingmetastatic castration-resistant prostate cancer and an effective amountof ¹⁷⁷Lu-PSMA I&T including ¹⁷⁷Lu-PSMA I&T having an optical excess ofstructure 2A) is administered to the subject to treat the prostatecancer.

The effective amount of ¹⁷⁷Lu-PSMA I&T (including ¹⁷⁷Lu-PSMA I&T havingan optical excess of structure 2A) radiopharmaceutical administered to apatient will generally be determined by considering the patient record.However, the effective amount suitably may be within a range of about0.1 GBq to 30 GBq per dose. More specifically, the dose may range fromabout 1 GBq to about 20 GBq or about 30 GBq per dose subject, forexample, about 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 6.8, 7,7.5, 8, 8.5, 9, 9.5, 10, 10.5, 11, 11.5, 12, 12.5, 13, 13.5, 14, 14.5,15, 15.5, 16, 16.5, 17, 17.5, 18, 18.5, 19, 19.5, 20, 21.5, 22, 22.5,23, 23.5, 24, 24.5, 25, 25.5, 26, 26.5, 27, 27.5, 28, 28.5, 29, 29.5 or30 GBq per dose of ¹⁷⁷Lu-PSMA I&T (including ¹⁷⁷Lu-PSMA I&T having anoptical excess of structure 2A), or any range between two of the abovevalues. The dose can be administered from a unit dose in a vial or asyringe or as a bulk solution in a vial or a syringe prepared from acold-kit prepared with lutetium-177 at a local or central nuclearpharmacy or through cGMP central manufacturing.

If necessary or desirable, the treatment may involve more than oneadministration of an effective amount of ¹⁷⁷Lu-PSMA I&T (including¹⁷⁷Lu-PSMA I&T having an optical excess of structure 2A). It isgenerally beneficial to repeat the administration of ¹⁷⁷Lu-PSMA I&T(including ¹⁷⁷Lu-PSMA I&T having an optical excess of structure 2A) tothe subject after 7 to 56 days, such as at a 4 to 8 week interval.

In a particularly preferred protocol, the ¹⁷⁷Lu-PSMA I&T (including¹⁷⁷Lu-PSMA I&T having an optical excess of structure 2A) dosage form isa sterile aqueous solution that is administered by intravenousinjection. The dosing regimen may include multiple infusions such as 1,2, 3, 4, 5, 6, 7, 8, 9 or 10 infusions at effective dosages such as of6.8 GBq +/−10% each, administered about 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10weeks apart.

Combination Therapy

¹⁷⁷Lu-PSMA I&T (including structures 2A and/or 2B above) suitably may beadministered to a subject in conjunction or combination with one or moreother therapeutic agents, particularly one or more otherchemotherapeutic agents.

In one aspect, a subject may receive treatment with ¹⁷⁷Lu-PSMA I&T(including structures 2A and/or 2B above) in combination with a regimeof docetaxel and/or prednisone, particularly for a subject sufferingfrom castration resistant prostate cancer.

In another aspect, a subject may receive treatment with ¹⁷⁷Lu-PSMA I&T(including structures 2A and/or 2B above) in combination with a regimethat can include chemotherapy such as docetaxel; cisplatin; gemcitabine;cisplatin/gemcitabine; cabazitaxel; one or more antiandrogens such asone or more LHRH agonists, such as leuprolide and goserelin, orantagonists (e.g. firmagon and relugolyx); one or more antiandrogenssuch as flutamide, nilutamide, bicalutamide, cyproterone, abiraterone,enzalutamide, darolutamide and apalutamide; one or more PARP inhibitorssuch as olaparib, rucaparib or niraparib, particularly for a subjectsuffering from prostate cancer including metastatic castration resistantprostate cancer.

In additional aspects, a subject may receive treatment with ¹⁷⁷Lu-PSMAI&T (including structures 2A and/or 2B above) in combination with animmunotherapy regime which may include adoptive cell therapies oradoptive immunotherapy.

For example, to treat a patient suffering from cancer, ¹⁷⁷Lu-PSMA I&T(including structures 2A and/or 2B above) may be administered incombination with immune effector cells (e.g., T cells, NK cells)engineered to express a Chimeric Antigen Receptor (e.g. CAR T-celltherapy), including to treat a cancer or a disease associated withexpression of a tumor antigen.

For a patient suffering from cancer including prostate cancer,¹⁷⁷Lu-PSMA I&T (including structures 2A and/or 2B above) also may beadministered in combination with other immune-based therapies such assipuleucel-T (Provenge) or other immune-boosting approaches includingantibody treatments. For instance, in one protocol, ¹⁷⁷Lu-PSMA I&T(including structures 2A and/or 2B above) may be administered incombination with one or more monoclonal antibodies such as pembrolizumab(Keytruda), ipilimumab (Yervoy) and/or nivolumab (Opdivo) for treating apatient suffering from cancer, particularly prostate cancer.

As used herein, the term “in combination” in the context of theadministration of a therapy to a subject refers to the use of more thanone therapy for therapeutic benefit. The term “in combination” in thecontext of the administration can also refer to the prophylactic use ofa therapy to a subject when used with at least one additional therapy.The use of the term “in combination” does not restrict the order inwhich the therapies (e.g., a first and second therapy) are administeredto a subject. A therapy can be administered prior to (e.g., 1 minute, 5minutes, 15 minutes, 30 minutes, 45 minutes, 1 hour, 2 hours, 4 hours, 6hours, 12 hours, 24 hours, 48 hours, 72 hours, 96 hours, 1 week, 2weeks, 3 weeks, 4 weeks, 5 weeks, 6 weeks, 8 weeks, or 12 weeks before),concomitantly with, or subsequent to (e.g., 1 minute, 5 minutes, 15minutes, 30 minutes, 45 minutes, 1 hour, 2 hours, 4 hours, 6 hours, 12hours, 24 hours, 48 hours, 72 hours, 96 hours, 1 week, 2 weeks, 3 weeks,4 weeks, 5 weeks, 6 weeks, 8 weeks, or 12 weeks after) theadministration of a second therapy to a subject in need of treatment asdisclosed herein. The therapies are administered to a subject in asequence and within a time interval such that the therapies can acttogether. In a particular embodiment, the therapies are administered toa subject in a sequence and within a time interval such that theyprovide an increased benefit than if they were administered otherwise.Any additional therapy can be administered in any order with the otheradditional therapy.

Packaged ¹⁷⁷Lu-PSMA I&T and Kits

As discussed above, treatment kits are also provided, including coldkits where the ¹⁷⁷Lu-PSMA I&T (including structures 2A and/or 2B above)can be prepared shortly before administration such as in a medicalfacility, for example a hospital laboratory or nuclear pharmacy. In sucha kit, EuK-Sub-kf-iodo-y-DOTAGA may be provided in a vial or othercontainer in lyophilized or other form separate from lutetium-177. TheEuK-Sub-kf-iodo-y-DOTAGA and lutetium-177 are reacted as disclosedherein at the medical facility to provide ¹⁷⁷Lu-PSMA I&T (including 2Aand/or 2B above) which then can be promptly administered to a patient.

In a further aspect, packaged preparations or products of ¹⁷⁷Lu-PSMA I&T(including structures 2A and/or 2B above) are also provided. A packagedpreparation may comprise 1) ¹⁷⁷Lu-PSMA I&T and optionally 2)instructions for using ¹⁷⁷Lu-PSMA I&T for treating a cancer such asprostate cancer. Preferably, the packaged preparation will comprise atherapeutically effective amount of ¹⁷⁷Lu-PSMA I&T (including structures2A and/or 2B above).

In certain exemplary packaged preparations or products, ¹⁷⁷Lu-PSMA I&T(including structures 2A and/or 2B above) suitably can be packaged insuitable containers labeled, for example, for use as a therapy to treata subject suffering from prostate cancer. The containers can include¹⁷⁷Lu-PSMA I&T and suitably one or more ascorbate compounds and one ormore gentisate compounds as disclosed herein. A product can include acontainer (e.g., a vial or the like) containing ¹⁷⁷Lu-PSMA I&T. Inaddition, an article of manufacture or kit further may include, forexample, packaging materials, instructions for use, syringes, deliverydevices, for treating the targeted condition, such as prostate cancer orother cancer.

A packaged system or product may also include a legend (e.g., a printedlabel or insert or other medium (e.g., an audio or video file)describing the product's use). The legend can be associated with thecontainer (e.g., affixed to the container) and can describe the mannerin which the compositions therein should be administered (e.g., thefrequency and route of administration), indications therefor, and otheruses. The compositions can be ready for administration (e.g., present indose-appropriate units), and may include one or more additionalpharmaceutically acceptable adjuvants, carriers or other diluents.

The following non-limiting examples are illustrative.

EXAMPLE 1

Radiolabeling was performed using no-carrier added ¹⁷⁷LuCl₃.Radiolabeling was done either directly in the isotope vial, ortransferred to a 20 mL vial. ¹⁷⁷Lu-PSMA-I&T is prepared as described inWeineisen et al. J Nucl Med 2015; 56:1169-1176 by use of racemicEuK-Sub-kf-iodo-y-DOTAGA. ¹⁷⁷Lu-PSMA I&T having an optical excess ofstructure 2A is also prepared as described in Weineisen et al. JNucl Med2015; 56:1169-1176 using the R-isomer of EuK-Sub-kf-iodo-y-DOTAGA (i.e.the compound of structure 1A above). The racemic ¹⁷⁷Lu-PSMA-I&T or¹⁷⁷Lu-PSMA I&T having an optical excess of structure 2A was dilutedusing reaction buffer and was added to a reaction vial to form aReaction Composition. A thus prepared Reaction Composition was heatedwith mixing using a shaker at 90 +/−4 ° C. Different reaction times andcool down periods were tested during development, ranging from 10 to 30minutes of labelling time and 0 to 20 minutes of cool down time. Threedifferent Reaction Compositions ((A), (B) and (C) set forth below) wereassessed.

The formulated racemic ¹⁷⁷Lu-PSMA-I&T and ¹⁷⁷Lu-PSMA I&T having anoptical excess of structure 2A batches were sampled for quality controltesting and tested for stability for up to 6 days post-day ofmanufacture. Batches of both 1) racemic ¹⁷⁷Lu-PSMA-I&T and 2) ¹⁷⁷Lu-PSMAI&T having an optical excess of structure 2A at room temperature (25°C.) and 2-8 ° C. storage were evaluated during development.Reverse-phase HPLC with radiometric and UV detection and thin layerchromatography with radiometric detection were used to assess chemicaland radiochemical impurities.

(1) Reaction Buffer Compositions evaluated:

-   -   (A)99 to 247 mg/mL Ascorbate (pH 4.5 to 6), made from sodium        L-ascorbate and ascorbic acid (preferred condition 162 mg/mL, pH        5.5 to 6.0)    -   (B) 5.1 to 12.5 mg/mL Gentisic Acid (0.4 M acetate used as        buffer, pH 5-6.5), made from gentisic acid    -   (C) 100 mg/mL Ascorbate with 5.0 mg/mL Gentisic Acid (pH 5-6.5),        made from sodium L-ascorbate, ascorbic acid and gentisic acid    -   (D)Reaction Buffer Compositions were diluted 1.48:1-0.4 N HCl:        Reaction buffer

(2) Formulation Buffer Compositions evaluated:

-   -   (A)65 to 68 mg/mL Ascorbate with 25 to 28 mg/mL Gentisic Acid        (pH 6-7), made from sodium L-ascorbate and gentisic acid        (preferred condition)    -   (B) 64 to 86 mg/mL Ascorbate (pH 6-7), made from sodium        L-ascorbate    -   (C) Formulation Buffer Compositions were diluted        11.5:1—Formulation Buffer:Reaction Composition

The conditions as set forth in the following Table 1 were evaluated:

TABLE 1 Radioactivity Formulation Concentration Reaction CompositionsCompositions at Activity Gentisic Acetate Reaction Gentisic ReferenceAcid Ascorbate (buffer) Time (Min) Acid Ascorbate Time Experiment 1 +− + 30 − + 0.93 Experiment 2 + − + 30 − + 0.97 Experiment 3a + − + 20− + 0.53 Experiment 3b + − + 20 + + 0.48 Experiment 3c + + − 20 − + 0.58Experiment 3d + + − 20 + + 0.56 Experiment 4a − + − 20 + + 0.49Experiment 4b − + − 20 + + 0.49 Experiment 4c + + − 20 + + 0.49Experiment 4d + + − 20 + + 0.49 Experiment 5a + − + 20 + + 0.49Experiment 5b − + − 20 + + 0.49 Experiment 6a + − + 20 + + 0.49Experiment 6b − + − 20 + + 0.49 Experiment 7 − + − 20 + + 0.49Experiment 8 − + − 15 + + 0.49 Experiment 9 − + − 10 + + 0.49 Experiment10 − + − 10 + + 0.49 Experiment 11 − + − 10 + + 0.49 Experiment 12 − + −10 + + 0.49

In each of Examples 1, 2, 3a, 3b, 3c, 3d, 4a, 4b, 4c and 4d, racemicEuK-Sub-kf-iodo-y-DOTAGA and racemic ¹⁷⁷Lu-PSMA I&T was used. In each ofExamples 5a, 5b, 6a, 6b, 7, 8, 9, 10, 11 and 12 R-isomer enrichedEuK-Sub-kf-iodo-y-DOTAGA (1A above) and ¹⁷⁷Lu-PSMA I&T having an opticalexcess of structure 2A were used.

Results: 1. Lu-177 Incorporation:

Chromatography shows the amount of Lu-177 incorporated into theEuK-Sub-kf-iodo-y-DOTAGA was >99.5% for all reactions at completion ofproduction. This demonstrates that under all conditions, including areaction time limited to 10 minutes, full incorporation of Lu-177 intoEuK-Sub-kf-iodo-y-DOTAGA was achieved. The ability to incorporate Lu-177in a reduced time, reduced the number of impurities at the end ofproduction.

2. Negative Impact of Gentisic Acid in the Reaction Composition(Incorporation Reaction):

In each of Experiments 1 and 2, gentisic acid was present in theReaction Composition, but the amount of gentisic acid present in theReaction Composition was double in Example 2 relative to Example 1.Specifically, in Experiment 1, 2.5 mg/mL of gentisic acid was used inthe Reaction Composition; and in Experiment 2, 5.0 mg/mL of gentisicacid was used in the Reaction Composition. Over the 5 or 6 dayevaluation period, it was found that radiochemical purity dropped 5% forthe Experiment 1 sample and radiochemical purity dropped 13% for theExperiment 2 sample.

Experiments 3 through 6 demonstrated that the inclusion of only gentisicacid in the reaction results in an impurity peak that elutes at ˜10.2min; this peak is absent when only ascorbate is used. When gentisic acidand ascorbate are both used in the reaction, the peak at ˜10.2 min alsomay be present (see FIGS. 1A-1D) in certain instances. Therefore, tominimize impurities, gentisic acid may be excluded from theincorporation reaction.

3. HPLC Verification

In FIG. 1A, HPLC shows an incorporation reaction with acetate andgentisic acid (peak at 10.2 min always appears): 20 min reactions at 90°C. In FIGS. 1B-1C, HPLC shows reactions with gentisic acid and ascorbate(peak at 10.2 min appears sometimes): 20 min reactions at 90 ° C. InFIG. 1D, HPLC shows reaction with just ascorbate (peak at ˜10.2 minnever appears): 20 min reactions at 90° C.

4. Positive Impact of Gentisic Acid in the Formulation Composition

It was found that inclusion of gentisic acid in the FormulationComposition at the time of or following termination of the reactionincorporating Lu-177 with EuK-Sub-kf-iodo-y-DOTAGA favorably impactedradiochemical purity of the racemic ¹⁷⁷Lu-PSMA-I&T or ¹⁷⁷Lu-PSMA I&Thaving an optical excess of structure 2A. That is, inclusion of gentisicacid in the Formulation Composition showed a reduced drop inradiochemical purity over time. Thus, over the 5 or 6 day evaluationperiod, in Experiment 3c where gentisic acid was not present in theFormulation Composition, radiochemical purity dropped 10.2%, whereas inExperiment 3d where gentisic acid was present in the FormulationComposition, radiochemical purity dropped 7.6%.

EXAMPLE 2

Further evaluations were conducted as follows. In Table 2, Conditions1-8 that are not reported in Example 1 are indicated by bold text.Experiments 1, 2, 3a-3d, 4a-4d, 5a-5b and 6a,6b in Table 2 below thatare also disclosed in Example 1 above are without bold text in Table 2below.

Radiolabeling was performed using no-carrier added ¹⁷⁷LuCl₃.Radiolabeling was done either directly in the isotope vial, ortransferred to a 20 mL vial. ¹⁷⁷Lu-PSMA-I&T is prepared as describedherein and in Weineisen et al. J Nucl Med 2015; 56:1169-117 by use ofracemic EuK-Sub-kf-iodo-y-DOTAGA. ¹⁷⁷Lu-PSMA I&T having an opticalexcess of structure 2A is also prepared as described in Weineisen et al.J Nucl Med 2015; 56:1169-1176 using the R-isomer ofEuK-Sub-kf-iodo-y-DOTAGA (i.e. the compound of structure 1A above).¹⁷⁷Lu-PSMA-I&T is also commercially available. The racemic¹⁷⁷Lu-PSMA-I&T or ¹⁷⁷Lu-PSMA I&T having an optical excess of structure2A was diluted using reaction buffer and was added to a reaction vial toform a Reaction Composition. A thus prepared Reaction Composition washeated as per the method followed. Different reaction times were testedduring development, ranging from 10 to 30 mins of labelling time. Threedifferent Reaction Compositions ((A), (B) and (C) set forth below) wereassessed.

The formulated racemic ¹⁷⁷Lu-PSMA-I&T and ¹⁷⁷Lu-PSMA I&T having anoptical excess of structure 2A batches were sampled for quality controltesting and tested for stability for up to 6 days post-day ofmanufacture. Batches of both racemic ¹⁷⁷Lu-PSMA-I&T and ¹⁷⁷Lu-PSMA I&Thaving an optical excess of structure 2A at room temperature (25° C.)and 2-8 ° C. storage were evaluated during development. Reverse-phaseHPLC with radiometric and UV detection and thin layer chromatographywith radiometric detection were used to assess chemical andradiochemical impurities.

(3) Reaction Compositions evaluated at precursor amounts of 125 to 250μg:

-   -   (A) 40 to 100 mg/mL Ascorbate (pH 4.5 to 6), made from sodium        L-ascorbate and ascorbic acid (preferred condition 65 mg/mL, pH        5.5 to 6.0)    -   (B) 2.0 to 9.8 mg/mL Gentisic Acid (27 to 35 mg/mL acetate used        as buffer, pH 5-6.5), made from Gentisic acid (pH 5-6.5)    -   (C) 40 mg/mL Ascorbate with 2.0 to 2.1 mg/mL Gentisic Acid, made        from sodium L-ascorbate, ascorbic acid and gentisic acid

(4) Formulation Compositions evaluated:

-   -   (A) 1 mg/mL Gentistic Acid (27 to 35 mg/mL acetate used as a        buffer, pH 5.5), made from Gentisic acid    -   (B) 59 to 79 mg/mL Ascorbate with 0.16 to 26 mg/mL Gentisic Acid        (pH 6-7), made from sodium L-ascorbate and gentisic acid        (preferred condition)

The conditions as set forth in the following Table 2 were evaluated:

TABLE 2 Formulation Compositions Reaction Compositions (with¹⁷⁷Lu-PSMA-I&T) Gentisic Reaction Time Gentisic Sodium Acid Ascorbate(Min) / Temp Acid Ascorbate Reference (mg/mL) (mg/mL) Buffer (° C.(mg/mL) (mg/mL) Isomer RAC² Condition 1 0 0 MES¹ 20 / 95 0 0 R-isomer0.81 Condition 2 3.3 0 Sodium 30 / 90 1 0 R-isomer 0.74 AcetateCondition 3 0 0 Sodium 30 / 90 1 0 R-isomer 0.74 Acetate Condition 4 9.80 Sodium 20 / 90 25 58 R-isomer 0.79 Acetate Condition 5 0 65 none 10 /90 26 66 R-isomer Condition 6 0 80 none 10 / 80 26 66 R-isomer 0.47Condition 7 0 80 none 10 / 70 26 66 R-isomer 0.47 Condition 8 0 80 none10 / 60 26 66 R-isomer 0.47 Experiment 1 2.5 0 Sodium 30 / 90 0.20 59racemic 0.93 Acetate Experiment 2 5.0 0 Sodium 30 / 90 0.40 68 racemic0.97 Acetate Experiment 3a 2.1 0 Sodium 20 / 90 0.16 79 racemic 0.53Acetate Experiment 3b 2.1 0 Sodium 20 / 90 24 59 racemic 0.48 AcetateExperiment 3c 2.1 40 none 20 / 90 0.16 82 racemic 0.58 Experiment 3d 2.140 none 20 / 90 24 62 racemic 0.56 Experiment 4a 0 40 none 20 / 90 23 62racemic 0.49 Experiment 4b 0 40 none 20 / 90 26 62 racemic 0.49 [1/2RAC] Experiment 4c 2.0 40 none 20 / 90 23 62 racemic 0.49 [1/2 RAC]Experiment 4d 2.0 40 none 20 / 90 26 62 racemic 0.49 Experiment 5a 3.3 0Sodium 20 / 90 23 62 R-isomer 0.49 Acetate Experiment 5b 0 65 none 20 /90 23 64 R-isomer 0.49 Experiment 6a 0 0 none 20 / 90 23 62 R-isomer0.49 Experiment 6b 0 100 none 20 / 90 23 63 R-isomer 0.49 Experiment 7 065 none 20 / 90 23 63 R-isomer 0.49 Experiment 8 0 65 none 15 / 90 26 66R-isomer 0.49 Experiment 9 0 65 none 10 / 90 26 66 R-isomer 0.49 ¹MES =2-(N-morpholino)ethanesulfonic acid ²RAC = Radioactivity Concentrationat Activity Reference Time

Results: 1. Incorporation Reaction and Formulation Compositions forCondition 1, 2 and 3 in Table 2

Radiolabeling was performed using no-carrier added ¹⁷⁷LuCl₃ followingthe radiolabeling conditions described by Weineisen et al. J Nucl Med2015; 56:1169-1176 and Chatalic et al. Theranositcs 2016; 6:849-861(Chatalic) for the preparation of ¹⁷⁷Lu-PSMA-I&T for pre-clinical orclinical use. Thin layer chromatography shows the amount of Lu-177incorporated into the EuK-Sub-kf-iodo-y-DOTAGA was >99.5% for allreactions at completion of production at reaction temperatures of 95° C.and 90° C. for 20 and 30 minutes. The conditions are described in Table2 above.

Batches of both racemic ¹⁷⁷Lu-PSMA-I&T and ¹⁷⁷Lu-PSMA I&T having anoptical excess of structure 2A at room temperature (25° C.) and 2-8° C.storage were evaluated during development. Reverse-phase HPLC withradiometric and UV detection and thin layer chromatography withradiometric detection were used to assess chemical and radiochemicalimpurities.

HPLC showed that radiochemical purity was 96.7% for Condition 2, 87.4%for Condition 3 and 87.4% for Condition 1 post-formulation. After twodays, the radiochemical purity was 78.3% for Condition 2, 70.7% forCondition 3 and 27% for Condition 1 at room temperature, respectively.After six days, the radiochemical purity was 58.0% for Condition 2,55.6% for Condition 3 and 4.3% for Condition 1 at room temperature,respectively. These results demonstrate that the preparation of¹⁷⁷Lu-PSMA-I&T under such conditions requires heating above 90° C. forgreater than 20 minutes, the incorporation conditions yield a productwith radiochemical purity <97% at the time of formulation and a rapiddrop in radiochemical purity over time is observed and is related to theformation of a greater number of ¹⁷⁷Lu-PSMA-I&T related impurities.

2. Incorporation Reaction and Formulation Compositions

The following procedures were utilized for Conditions 4-8 andExperiments 1, 3a-3d, 4a-4d, 5a-5b and 6a,6b with radiolabeling wasperformed using no-carrier added ¹⁷⁷LuCl₃ following the radiolabelingconditions set forth in Table 2 above. Thin layer chromatography or HPLCshows the amount of Lu-177 incorporated into theEuK-Sub-kf-iodo-y-DOTAGA was >99.5% for all reactions at completion ofproduction at reaction temperatures of 90° C. for 30 minutes, andsurprising for as short 10 min at only 60° C. HPLC showed thatradiochemical purity was 99.2% post incorporation reaction for Condition4 and the radiochemical purity for Condition 2 was 99.4% postincorporation reaction. After two days the radiochemical purity forCondition 4 is 99.1% at room temperature and after two days theradiochemical purity for Condition 5 is 99.2% at room temperature. Aftersix days the radiochemical purity for Condition 4 is 97.6% at roomtemperature and Condition 5 is 96.9% at room temperature. Thepreparation of ¹⁷⁷Lu-PSMA-I&T following the conditions described inCondition 4 and Condition 5, demonstrates for the first time a productthat is >99% pure post incorporation reaction and maintains >95%radiochemical purity over 6 days at room temperature in the FormulationComposition. In addition, ¹⁷⁷Lu-PSMA-I&T was formed under milderconditions (60° C.) for as little as 10 minutes.

3. Negative Impact of Gentisic Acid on Product Purity and Stability whenIncluded in the Reaction Composition (Incorporation Reaction):

In FIG. 1A (Experiment 3a), the HPLC chromatogram shown for anincorporation reaction with acetate and gentisic acid has a peak at 10.2min that is consistent with a gentisate adduct impurity. The same peakis found in the HPLC chromatograms for Condition 4, Experiments 1, 2,3a, 3b, 3c, 3d, 5a, 6a and Condition 2. In FIGS. 1B-1C (Experiment 3cand 4d), the HPLC chromatograms show an incorporation reaction withgentisic acid and ascorbate where the gentisate adduct impurity is notconsistently formed, i.e. the peak at 10.2 min, even through gentisateis present. This inconsistency in the formation the gentisate adductimpurity is consistent with the results of Experiments 3d and 4c. InFIG. 1D (Experiment 4a), the HPLC chromatogram shown for anincorporation reaction with just ascorbate the gentisate adduct impurityis not formed, i.e. the peak at 10.2 min is absent. The same result,i.e. lack of the gentisate adduct impurity, was also found forConditions 5, 7 and 8, Experiments 4a, 4b, 5b, 6b, 7, 8, 9, 10, 11 and12 where only ascorbate was present in the incorporation reaction. InFIG. 1E and 1F (Condition 3 and Condition 1 respectively), the HPLCchromatogram shown for an incorporation reaction with acetate or2-(N-morpholino)ethanesulfonic acid that does not have a peak at 10.2min.

Therefore, to minimize impurities, gentisic acid may be excluded fromthe incorporation reaction.

To maintain high radiochemical purity during the incorporation reactionand during storage, ascorbate must be included in the incorporationreaction.

4. Positive Impact of Gentisic Acid in the Formulation Composition

It was found that inclusion of gentisic acid in combination with anascorbate compound in the Formulation Composition at the time of orfollowing termination of the reaction incorporating Lu-177 withEuK-Sub-kf-iodo-y-DOTAGA favorably impacted radiochemical purity of theracemic ¹⁷⁷Lu-PSMA-I&T or ¹⁷⁷Lu-PSMA I&T having an optical excess ofstructure 2A. That is, inclusion of gentisic acid in the FormulationComposition showed a reduced drop in radiochemical purity over time without the formation of the gentisate adduct impurity (see FIG. 1D, whichis consistent with Conditions 5, 7 and 8, Experiments 4a, 4b, 5b, 6a,6b, 7, 8 and 12). Thus, over the 5 or 6 day evaluation period, inExperiment 3c where gentisic acid was not present in the FormulationComposition, radiochemical purity dropped 10.2%, whereas in Experiment3d where gentisic acid was present in the Formulation Composition,radiochemical purity dropped 7.6%.

EXAMPLE 3

The following is a preferred preparation process as also generallydepicted schematically in FIG. 2.

(1) Prepare all Solutions

-   -   a. Reaction Buffer prepared by combining sodium L-ascorbate and        ascorbic acid to yield approximately 162 mg/mL Ascorbate (pH        5.5-6).    -   b. Formulation Buffer prepared by combining sodium L-ascorbate        and gentisic acid to yield approximately 66 mg/mL Sodium        Ascorbate with approximately 28 mg/mL Gentisic acid (pH 6-7).    -   c. 0.04 N HCl    -   (2) Using Reaction Buffer, dissolve 250 ug of precursor (i.e.        racemic EuK-Sub-kf-iodo-y-DOTAGA or R-isomer of        EuK-Sub-kf-iodo-y-DOTAGA (compound of formula 1A)) to        approximately 424 μg/mL (Precursor Solution).    -   (3) Add additional 0.04N HCl to the lutetium-177 vial (Reaction        vial) in order to achieve a radioactive concentration of 7.8        GBq/mL).    -   (4) Add sufficient quantity of the Precursor Solution to the        lutetium-177 vial (Reaction vial) containing no-carrier added        lutetium-177 in 0.4 N HCl    -   (5) Heat vial containing the Reaction Composition in an aluminum        block with heating at 90 +/−4° C. and shaking at 300 rpm for 10        +/−1 min.    -   (6) Add Formulation Buffer into vial (Formulation vial) and mix        the Reaction vial to ensure homogeneity of the contents.    -   (7) Sterile filter diluted ¹⁷⁷Lu-PSMA-I&T (through 2×0.22 μm        filters) into a vial or IV bag.    -   (8) Rinse Reaction Vial with a sufficient quantity of and        sterile filter rinse (through 2×0.22 μm filters) into a vial or        IV bag with the diluted 177Lu-PSMA-I&T.    -   (9) Add further Formulation Buffer to yield final bulk drug        product in the Formulation Composition.    -   (10) Dispense fixed volume doses calibrated to a suitable number        of days post-manufacturing.

The above process also can be utilized to prepare ¹⁷⁷Lu-PSMA I&T that issubstantially optically enriched with or is an enantiomerically puremixture of the S-isomer of ¹⁷⁷Lu-PSMA I&T (compound of structure 2Babove) by use of the S-isomer of EuK-Sub-kf-iodo-y-DOTAGA (compound ofstructure 1B)).

EXAMPLE 4

Treatment Protocol

A human male patient is selected for treatment after being diagnosedwith metastatic castration-resistant prostate cancer (such as manifestedby progression of the disease despite surgical or chemical castration)who have progressed following treatment first line androgenreceptor-axis-targeted (ARAT) therapies.

¹⁷⁷Lu-PSMA I&T having an optical excess of structure 2A in a sterileaqueous solution is administered by intravenous injection. The dosingregimen may include four infusions of 6.8 GBq +/−10% each, administered8 weeks apart.

INCORPORATION BY REFERENCE

The entire contents of all patents, published patent applications andother disclosures cited herein are hereby expressly incorporated hereinin their entireties by reference.

1-70. (canceled)
 71. A pharmaceutical composition comprising: (a) acomplex of lutetium-177 and EuK-Sub-kf-iodo-y-DOTAGA; (b) one or moreascorbate compounds.
 72. The composition of claim 71 wherein thecomposition is free of a gentisate adduct impurity.
 73. The compositionof claim 71 wherein the composition comprises one or more gentisatecompounds.
 74. The composition of claim 71 wherein the composition is anaqueous formulation.
 75. The composition of claim 71 wherein the complexof lutetium-177 and EuK-Sub-kf-iodo-y-DOTAGA comprises in optical excessthe following structure:


76. The composition of claim 71 wherein the complex of lutetium-177 andEuK-Sub-kf-iodo-y-DOTAGA comprises in optical excess the followingstructure:


77. A pharmaceutical composition comprising: (a) a complex oflutetium-177 and EuK-Sub-kf-iodo-y-DOTAGA; (b) one or more stabilizercompounds, wherein the composition at least substantially free of agentisate acid adduct impurity.
 78. A method for treating a patientsuffering from cancer, comprising: a) admixing 1) lutetium-177, 2)EuK-Sub-kf-iodo-y-DOTAGA in the substantial or complete absence of agentisate compound, and 3) one or more stabilizer compounds; b) heatingthe admixed 1) lutetium-177 and 2) EuK-Sub-kf-iodo-y-DOTAGA in thesubstantial or complete absence of a gentisate compound, wherein acomplex of lutetium-177 and EuK-Sub-kf-iodo-y-DOTAGA is formed in theabsence of a gentisate compound; and c) administering the complex oflutetium-177 and EuK-Sub-kf-iodo-y-DOTAGA to the patient.
 79. The methodof claim 78 wherein the subject is suffering from prostate cancer. 80.The method of claim 78 wherein 1) lutetium-177, 2)EuK-Sub-kf-iodo-y-DOTAGA and 3) one or more stabilizer compounds areadmixed in the absence of a gentisate compound.
 81. The method of claim78 wherein 1) lutetium-177, 2) EuK-Sub-kf-iodo-y-DOTAGA and 3) one ormore stabilizer compounds are heated in the absence of a gentisatecompound.
 82. The method of claim 78 wherein one or more ascorbatecompounds are admixed with 1) lutetium-177 and 2)EuK-Sub-kf-iodo-y-DOTAGA.
 83. The method of claim 78 further comprisingadding one or more ascorbate compounds to the complex of lutetium-177and EuK-Sub-kf-iodo-y-DOTAGA.
 84. The method of claim 83 wherein the onemore gentisate compounds are added while or after heating is reduced orterminated.
 85. The method of claim 78 further comprising adding one ormore gentisate compounds to the complex of lutetium-177 andEuK-Sub-kf-iodo-y-DOTAGA.
 86. The method of claim 83 further comprisingadding one or more gentisate compounds to the complex of lutetium-177and EuK-Sub-kf-iodo-y-DOTAGA.
 87. The method of claim 85 wherein the onemore gentisate compounds are added while or after heating is reduced orterminated.
 88. The method of claim 86 wherein the one more gentisatecompounds are added while or after heating is reduced or terminated. 89.The method of claim 80 wherein the complex of lutetium-177 andEuK-Sub-kf-iodo-y-DOTAGA does not contain an impurity having a relativeretention time of approximately of 9 to 12 minutes by high-performanceliquid chromatography.
 90. A complex of lutetium-177 andEuK-Sub-kf-iodo-y-DOTAGA obtainable by a method comprising: a)admixing 1) lutetium-177, 2) EuK-Sub-kf-iodo-y-DOTAGA in the substantialor complete absence of a gentisate compound, and 3) one or morestabilizer compounds; and b) heating the admixed 1) lutetium-177 and 2)EuK-Sub-kf-iodo-y-DOTAGA in the substantial or complete absence of agentisate compound, wherein a complex of lutetium-177 andEuK-Sub-kf-iodo-y-DOTAGA is formed in the absence of a gentisatecompound.
 91. A pharmaceutical composition comprising a complex of claim90.
 92. The pharmaceutical composition of claim 91 wherein the complexcomprising the following compound in optical excess:


93. The pharmaceutical composition of claim 91 wherein the complexcomprising the following compound in optical excess:


94. The pharmaceutical composition of claim 91 wherein the compositioncomprises one or more stabilizer compounds.
 95. The pharmaceuticalcomposition of claim 91 wherein the composition comprises one or moreascorbate compounds.
 96. The pharmaceutical composition of claim 95wherein the composition comprises one or more gentisate compounds. 97.The pharmaceutical composition of claim 91 wherein the composition isfree of a gentisate adduct impurity.
 98. A method of treating a subjectsuffering from cancer, comprising administering to the subject aneffective amount of a composition of claim
 91. 99. The method of claim99 wherein the subject is suffering from prostate cancer.